G'day,
While I agree with some of what you say, I think it needs to be
considered against the alternatives.  In particular, the crew in your
video (very cool, exactly what Jan had in mind when we first discussed
Blind Date) could easily handle the rig with a little instruction and
no danger.  Put them on a conventionally rigged boat, (highly loaded
sheets to release and then pull in, winches to tail and wind, changing
sides/ends, getting in irons) and it would be a dangerous disaster.
Other comments follow yours

> The main thing is simply a matter of control. We have lots of shallow waters in the Netherlands. If you want to sail on the Waddenzee for example, you need to be able to sail with the rudders (almost) pulled up. This is impossible with an easy rig that is positioned in the middle of the leeward hull. End of story.

The rig does not have to be sailed with both the jib and the main.
Either can be lowered, under or over sheeted to move the balance point
forward and back in tight situations.  If the main is not used, you
will need a brace line to the front end of the boom, but this is not a
big deal.
>
> - I do not like the way an easy rig looks. It does not look 'aerodynamically right'. Usually if things do not look fast they are not fast.

That depends on who is doing the looking.  ;-)  The Wolfson Institue
in Southampton did some tests comparing the ballestron rig with
conventional sloop rigs.  The ballestron was very slightly slower
upwind, faster on a reach (particularly a broad reach when the
ballestron jib kept working, but the sloop genoa was not) and faster
downwind until the sloop poled out their genoa.  These results were
supported by real life tests by Yachting Monthly magazine on a couple
of Hirondelle cats and Yachting World magazine on a couple of 34'/11m
Sadler monos.  In both cases, the ease of use was a much more
commented upon feature than the superior speed.
>
> - It looks kind of unnatural because it seems to be lifted from the ship. It is not one with the ship.

That is due to the height of the boom.  I personally think that deck
sweeping headsails and low mainsails, while aerodynamically superior
(end plate effect) are extremely dangerous as they limit vision in the
most likely sector from which another boat will appear.  However, if
you can live with this, and the boom sweeping low over the deck during
tacks, gybes and shunts, then lowering the boom will improve the
aesthetics.
>
> - The look and feel is kind of lazy. Not interested, taking things too easy. Statical, almost dead.

Very few cruisers would agree with this!  However, for those who like
tweaking and hard work, it is easy to employ most of the trimming aids
that a normal rig uses. For example: mast bend (controlled with the
topping lift led to the boom end), mainsail twist (leech control line)
and camber (downhaul/cunningham), foot curve (outhaul), jib twist
(halyard and downhaul to adjust  location on the forestay), camber
(sheet and backstay to control headstay sag).  We used all these while
racing Rare Bird, but cruising we set and forget and let the bendy
mast do the lion's share of the trimming work.

> - The strongest forces are the vertical forces on the forestay and the leech of the mainsail. These enormous forces are countered by a boom that must be very strong and will be very heavy. This is not an elegant solution. It is brute force.

True but much less brute force than mainsheet travellers, deck tracks
for jibs, vangs and the beefing up, winches and multipart purchases
they require.  It is also possible to make a much more elegant boom,
but the prime requirement in the Vis was for low cost.
>

> - On the Blind Date the boom connected to the mast with a hinge. The result is that you can not trim the mainsail and the jib independently. You want much tension on the luff of the jib and little tension on the leech of the main. The topping lift could solve that problem, but that does not work on both bows. Two topping lifts would be better, but that would mean an extra line to take care of after every shunt. It would make it a little less easy rig.

Correct, but still far less work than trimming a conventional rig,
especially as bending the mast is only required in strong winds.  The
hinge (boom free to pitch around the mast) is optional. The engineer
made a good case for the pitching boom, but in retrospect I would not
use it again. There is no reason why you cannot use wedges to lock it
in position.
>
> - You can not sheet the mainsail and the jib independently. You can not steer the ship with the sails. You can not play with the waves and the sails.

See above.  Plus the most important part of playing with the jib
(altering shape and twist when sheets are eased) is done automatically
as the rig rotates. It is far more efficient in waves to trim the
entire rig with one lightly loaded sheet than it is to adjust two
sails independantly
>
> - There are situations where you want to let go the mainsail without changing the jib. For instance when you are overpowered in a gust.

Rotating/luffing the whole rig will always be more effective and more
efficient than sailing under jib with the main flapping.
>
> In strong winds the mast has so much friction that it does not turn when the sheet is released. Not safe.

 Definitely not safe!  The balance between the main and the jib on a
ballestron needs to be in favour of the main at all times.
>
> The COE (Center of Effort) is behind the mast. This is necessary to get some power on the sheet and to make the rig turn when the sheet is released. The result is momentum 1 that makes the ship want to turn its nose into the wind.
>
> The mast is placed on the leeward hull. The COE is on the leeward side of the ship. The result is momentum 2 that makes the ship want to turn its nose into the wind.
> Momentum 1 + momentum 2 make the ship by definition out of balance.
> The balance can only be restored by using big strong rudders. The back rudder is used as a daggerboard.
> This is again countering enormous forces with other brute forces: not elegant.

All correct, but a lot more elegant, simple, safer, lighter and
cheaper than a conventional rig with 2 rudders and two daggerboards,
plus their cases.
>
> In shallow waters, when you need to pull the rudders up, the ship will be out of control. Momentum 1 + 2 are not countered anymore. The ship will turn it's nose into the wind.

See above, plus the rudders can be built to be raised for shallow
water and for balance. I almost always sail my Elementarry with the
front rudder raised.
>
> Applied on the Visionarry proa's
>
> Visionarry looks modern, light, fast, like a flying saucer or a fighter plane, hi-tech. The aero rig looks old fashioned, slow, low-tech.
> On a light ship that is built for speed, control is a crucial factor. The aero rig is static and does not contribute to the control of the ship. It needs extra control for it self.

No more so than a conventional rig, but because the control is rarely
needed, none of the boats so far have bothered to fit it.

None of the above makes the easy rig perfect, but for short handed
performance cruising, I have not come across a better rig. The only
one that comes close is a schooner una rig, partly because it opens up
the lee hull for accommodation and gives a lot more balance options,
particularly while shunting. On the down side of the schooner is
higher sheet loads (possibly reduced by raking the mast forward in
it's bearings), poor upwind light air performance and more cost.

The other thing that should be taken into account is the extreme
(relatively speaking) light weight that is possible with a ballestron
on a proa. This is partly as it is unstayed, but the weight of all
the deck gear and strengthening required to utilise a conventional rig
adds a lot of weight, complexity and cost. A 15m multi with all of
Blind Dates space and attributes weighing 2 tonnes would not be
possible with any other type of rig.

There are a bunch of other rigs to try (wings, junks, crabclaw, kites,
etc), but none of them match the easyrig, in my experience. The
bigger the boat, the further ahead the easyrig gets.

regards,

rob