I would break up part of the 20 melee power/ranged power out of tier 5 and sprinkle it through the cores, even starting at the first, like 2 rp and melee power per core and make the tier 5 only 10 melee power/ranged power. Or something like that. I have not crunched the numbers fully.
this would further make splashing fighters worthy, even one level--not just a feat but more fight power.