I'll leave others to comment on the looks ... I choose my sails based on their performance and my objectives.
The short version is that the vented B / Pro will load up on centre whereas the Polo Revs don't due to the placement of the vents and the straighter leading edge. The Polo also has a higher rate of rotation due to a slight change in angle on the verticals - you loose some straight line precision in the trade.
As for the full sail - I can competently fly both pro and Polo in short line 3D situations and I'm comfortable with both. The full sail does not have a pronounced difference in sail loading like the vented, but the verticals cause the same rate of rotation difference.
Some people (like myself) want a sail to load up, others prefer having a light feeling from the kite. I have both sets and can fly them both solidly, but there is a distinct difference between the two. For myself, my choice is the Pro for the best all around sail.
I think there are varying definitions of 'tough' in these here parts ... and given the monopoly money we earn out here, I certainly wouldn't agree with some of them.
The indoor needs an update - which direction such an update takes will dictate my interest or not.
A crossover / hybrid would need to be able to take the outdoor condition if it is so intentioned. If it cannot, then label it an indoor only kite and leave it's outdoor flying to those with a far looser definition of tough than most.
The Zen is a fine wing for what it was designed to do .... long line team flying. Throw it onto 50' or 30' lines (my 2 most used lengths) and it's a different animal. For me it's not that I can't fly it, it's that it's not as enjoyable, requires a different mechanic and it's size can be problematic on such short lines.
If you just want to have some fabric in the air then the Zen and others are perfectly acceptable solutions. For me personally, if I have a Rev up I want to be able to perform more than just gliding around.
Just my goals and needs, those with different ones will see it differently. If a kite meets my needs then I will buy it .... if not, I cannot afford idle money sitting in my bag.