There have been some good results obtained at low speed with proper aerofoil machines ( Windflower being a good example), but they may not fall into your category of " pleasing to the eye". That is likely something that comes from traditional acceptance. If the Dutch type mills had never been produced and become familiar to us, I wonder how well they would be accepted if invented now.

If you have plenty of wind then there are a lot of things that will work. With a 9:1 gearing you can use a very efficient generator and in higher winds the loss from a decent chain drive will be small. If you can reduce the generator light load and bearing loss to near nothing then the chain may still let you manage something in lighter winds. If you must keep to the Dutch mill type blades rather than more efficient aerofoil ones designed for the low speed then you will probably not do a lot of good in a light wind area.

If local conditions or pressure from others force you to take this low speed route then it is not impossible to get reasonable results but it is not a logical approach for anyone not constrained to follow that path.

To get energy out of the air you have to slow it down and deflect it.  You can't take all the energy out - you need to leave some energy in the air to get the used air out of your blades and let new air come in and bring more energy with it.  (The max you can extract before extracting more gets you less is the "Betz limit".  That's 16/27 (59.3%))  But any energy you left in the air other than simply slowing it by Betz's amount - turbulence, sound, vortices, rotation, etc. - represents energy you didn't capture, i.e. a loss of efficiency.

Newton's first law says that if the wind applies a torque to your blades your blades will apply a torque to the wind.  That means the air leaves your blades with a spin to it.  This spin represents lost energy.

With a single layer of blades all moving in the same direction you can't cancel this torque out and capture that energy.  (And multiple layers of counterrotating blades to capture a couple extra percent of power is a reduction in the most important measure of efficiency:  Power per unit of investment.  B-)  )  So you want to keep the energy lost to "twisting the wind" low.

Power is force times distance, which (for a rotating system) means torque times RPM.  For a given amount of power you can run your blades fast (high speed, low torque) or slow (low speed, high torque).   The faster your blades, the lower they torque the wind, and the smaller the fraction of energy they waste by spinning the "exhaust".

When a windmill blade sweeps by, it decellerates, not just the air it touches directly, but air on both sides of the blade for a considerable distance as well.  It slows the upwind air by raising the pressure upstream of it, and (for lift-types) also slows the downwind air by lowering the pressure behind it.

So you have a slug of air that has had its energy extracted.  This slug moves downwind.  If the next blade comes by about the time the slug has moved by its own length (or by the length of the fully-slowed part of the slug plus half the length of the leading plus trailing partially-slowed parts), the next blade decellerates the NEXT slug of air and no air gets through the mill's cross-section without having the appropriate amount of energy pulled from it.

So aerodynamic solidity depends on the ratio of the depth of the affected air times the number of blades to the radius times the TSR.  A fast-moving blade doesn't have to be very wide to affect a deep slug of air (which is why lift type blades get NARROWER near the tips - which are moving faster and thus can be narrower to achieve the same along-wind-direction "reach".)