I think we can agree that the problem is that the PAT kick is boring and stupid, largely because it's so automatic. From there, you're making a leap to the solution being to make the PAT less automatic. To me, the simplest solution is to do away with it entirely (while keeping the option to gamble with the 7th point). My solution changes the game almost not at all (all TDs are 7 points, which they pretty much already are, and a try leaves you with either a 6-pt or an 8-pt TD, just like today), while getting rid of a boring and stupid play. Your solution changes the game dramatically (TDs are now worth 6.5 points on average, instead of 7).
None of this makes sense to me. The 7th point makes FGs less frequent than they would be without it. Anything that makes 6-point TDs more common will increase the frequency of FG attempts (unless you also make FGs more difficult, a la DLCassidy's proposal above). And I think we're in agreement that more FG attempts is bad and more going for it on 4th down is good.
I forgot to address another point before:
Agreed about the PAT: a 7-point TD dramatically reduces the likelihood of a tie at the end of regulation. Which is why your proposal would drive things the other way. The 2-point conversion has the opposite effect, though: it makes ties at the end of regulation much more frequent.