I totally agree with this suggestion. No prizes to guessing why ;)
With people worrying about teams tanking to accumulate money then "buying a championship", I think team chemistry is a good feature to minimize that, so I don't see why not. The only drawback could be that it requires a rewrite in the GE (or could it just need some minor tweaks? Idk coz I'm not a programmer. I just assume it's a lot of work).
Also, a minor performance bonus for home grown players would be great. In case anyone is wondering, monetary bonus for home grown and locals is not a lot. Out of my top 3 players (total salary of over 440k), 2 are my draftees and 1 is a local. The next 3 players have a salary of 33k, 25k, and 13k respectively, all my own draftees. I only earn 60k. Now imagine having built your team the normal way, with mixed foreigners and maybe 1 draftee who became your franchise player. How much would you earn? Not enough to move any needles really. Which is why it's easier to buy a team and win. Of course, giving boosts to draftees (tho I disagree to boost their skills by one level, maybe make it an effect like experience and game shape) won't directly stop people from tanking and buying a team. They can still tank to train then buy a team later on. But you need to invest enough in scouting (and be lucky enough) to land a HOF or ATG in the draft. You also need to invest quite a sum to build a proper training environment for your draftee, which if you do, would certainly put a dent to your finances, making it harder for you to just "buy a team and win" when your draftee hits his prime. So it makes "tanking to win" a much harder process.