Some quick answers, as I have to run:
I (we) own a 2003/04 200V. I don't know what current prices on used vehicles are, but, order of magnitude, the price seems reasonable to me. You should probably search some used vehicle prices, though. The 22,000 miles is somewhat of a concern to me, but not a deal-breaker. But why so few miles? Generally, like cars, RVs do better being used, so beware if it sat for long periods.
No drainage problem for me with aisle shower, and I haven't even heard of any. You need to be not on a steep slope, or the water will, obviously, flow in that direction, but I have had no drainage problems.
The AC pan may leak into the cabin if you are nose down. Never had a problem with it. Just be aware that parking with the front significantly lower than the rear will cause the water to flow forward. Again, just be reasonably close to (not perfectly, by any means) level.
I have no problems with handling or visibility. I haven't driven a 190 since I bought the 200, but I have no handling issues and haven't really heard of any.
We bought the 200V to be able to take our son and a friend camping with us. It is tight with four, but doable, especially when they are younger. Three works fine. The front beds are OK for kids, and adults in a pinch, but are really a bit short, narrow, and lumpy compared with a real bed. Having said that, we have used them, and they worked out fine.
Only problem we had was leakage into the rear window. That was fixed under warranty and it has not leaked since.
The 200 gives you enormous storage. Be careful not to overload it. I think you'll find it an excellent vehicle for a family with a young child. Hope this works out OK for you.