Lilith is one my favorit game devs so far, sure they charge u 60-100 dollar for a new hero but they listen to the community really well and do they best to meet u on the road so to speak.

I agree with the change, it was really needed late game as my troops would basiscly live in the hospital.

Then i would go Dwarf. What u also could do is spend all your resources on research that only benefits wall damage ( canons etc ) and dont research the stuff like riflemen etc. Have your house members borrow u units so u can fully focus on siege units.

As stated above u won't lose much in term of attack/hp. As for your question if it is worth it or not depends. you will have to start all over agian in your research. You will have to farm all those resources agian and since that server is about a month old it may be a little hard to farm those reso...