It's an interesting idea, though I find in most games I play that you only become more powerful in theory, because the power level of your enemies increases at least in line with your own power. A classic example would be WoW, where a Northrend bear is more deadly than any of the mages, liches, warlords and minor godlings you fought on the way there.
That's something I found slightly irritating in Prototype. Sure, by the end of the game you can sweep through the lowly rank and file like they're not there (though when can you not in that game) but the majority of opponents thrown at you towards the end are either annoyingly tough to handle (Super Soldiers, who are less vulnerable to your attacks than tanks and require lots of fiddly QTEs to beat them) or just plain immune to your best powers... so you end up ignoring your blades, your claws, your whip in favour of throwing heavy stuff at the final boss, which is a bit anticlimactic.
That's something I found slightly irritating in Prototype. Sure, by the end of the game you can sweep through the lowly rank and file like they're not there (though when can you not in that game) but the majority of opponents thrown at you towards the end are either annoyingly tough to handle (Super Soldiers, who are less vulnerable to your attacks than tanks and require lots of fiddly QTEs to beat them) or just plain immune to your best powers... so you end up ignoring your blades, your claws, your whip in favour of throwing heavy stuff at the final boss, which is a bit anticlimactic.