It is controlled to stack strength of 10 but do you mean it should be restricted to actual 10 unit stacks only?If they do that then I won't bother to play the game LoL.
Should it be only 10 units in a stack it won't stop a player to send 35 units in three stacks of 10 and one 5 unit stack to the target because it will do the same as sending the whole 35 unit stack, only the best 10 will perform and once they perish there will be back up units to continue the fight.
Try to adjust your tactics and strategy.A player won't be able to conquer all territory moving around with one single massive stack.Try to outflank it, attack it from different angles,lure it out,force your opponent to split his stack maybe then you can get the upper hand.
