I like the idea but one season to get 100% chemistry is a little bit too much imho. Sometimes teams have to sell/buy players for various reasons. (injury, wrong/bad planing, to good to be true deal on the transfermarket, no success -> less money from homegames...etc.)
Another idea would be to let Experience influence the "growth" of chemistry as well. Experienced players already know how to adjust to a new team/system. Younger players on the other hand might need more time to feel comfortable in a new surrounding. :)