Garens mark has a couple of problems
i seems rather... random. and it seems like he has no control over it.
- does it have limited range or does it work global?
- what happens if the mark applies to a low priority target, like that thresh who got the most recent kills by random lasthits, while the adc did 90% of the damage and didnt get many kills off it? (rare but situations like these happen)
- what happens in a teamfight when kills are exchanged and the mark possibly jumps from one target to the next? hes just about to finish the guy with the mark, then a kill causes it to jump to the next opponent?
- what happens if the mark applies to a champion he simply cant fight or reach? like kallista or an adc protected by a janna? ther eis a bunch of champions that can kite him pretty much indefinitely. here just a few examples
those are just a bunch i noticed while looking through the champion pool.
there are too many random factors playing into the way the target is chosen for my taste.
imo he should be able to chose his mark himself, but put heavy restrictions onto the ability to change it instead. for example, he cant change his mark until he has killed (and dealt justice to) the current one.
or there is an exceptionally long cooldown to the ability to switch the mark, so he cant change it willy nilly in a teamfight. and the enemy team can paly around it by protecting the marked target.
also, reading all these changes it sounds nice on the surface. but there is little chance that you added this mechanic to his kit without removing something in return. please be honest and tell us where you made cuts in his kit for this gimmick.
I love you...