I'd say a pop increase with any mixture and quantity of vet nerfs, reinforce cost increases, and nerfs to g43 moving dps (cooldown or accuracy). Not sure what number or combination (pop increase being a no brainer though), but I think those are the areas of issue with panzerfusiliers.
IMO, panzerfusiliers come out late enough as it is considering that their role overlaps (honestly, its basically the exact same) with that of volksgrenadiers, so a cp increase would just make them more awkward to work into a build.
Also on that point, I don't think that the issue with panzerfusiliers is that they come out too early (the kind of issue that a cp increase would remedy). It's that theyre extremely blobbable. This is because theyre low upkeep so you can spam them (6 popcap, which means youre only taxed 9 manpower a minute for a full squad of panzerfusiliers; and cost 24(?)25(?) per model to reinforce), because they have great moving dps (this allows them to chase down and wipe extremely well), because they have the ability to avoid HMGs due to the fact that they see HMGs before theyre in range of them (50 sight range i believe, 15 more than standard sight range, and 5 more than the range of an HMG), and because they have excellent vet. Another minor thing is that they can get the 3 g43s and still pick up another weapon off the ground (...3 g43s and an ober lmg34 with +20% and + 40% acc is scary, even if unlikely).
You have some very valid points, but i do disagree with 2 things.
First of all, Panzerfussies don't come too late, they come to early. 2CP is a rather low requirement for the firepower that they(the PF) can provide.
Second of all, They certainly do not overlap the role of volksgrenadiers but rather replace their role as a damage disher and receiver. What they should be (IMO) is much like Obersoldaten: staying in the back, taking safe shots at allied infantry while the volksgrenadiers take the punishment and focus since they are cheaper to reinforce. This is why me(and alot of other people in this thread) have called out for a higher popcap and reinforcement cost.
Other than that, i can agree with the rest of the post.