I think theres an easy way to fix this problem... they should just reduce the amount of exp you get per level so if you want to hang around level 3-5 longer to get those 3 star lvl 1-2's then just dont put any points in exp, granted it would pretty much screw over anyone who wasn't actually aware that people were like 4 levels higher then them... OR maybe you could just lock your exp too... Also I think they could just turn some units into like 6 gold costing units and you only see them when you are level 7 or higher.
There's several fixes, i've been experiencing the same thing you guys are, I tend to mitigate it by just forcing comps instead. With all the extra units now, its easy to get caught up buying too many units spreading yourself too thin. It's actually easier to get a 3 star 3 gold unit then a 1 star, you just have to pay attention to the drop rates and essentially the 3 gold units never dip below certain percentage after a certain level... Just position yourself accordingly and don't try to keep going for that 3 star trist/level 1 if you are past lvl 6 and only have 2/3rds of the total value.