Now I like to do all the secondary missions I come across but I soon realised doing this seems to make the storyline missions a complete joke. I've just killed the Bunker and associates, and I'm almost level 30, while the story missions I'm being given are all around level 25. Sure; the bonus missions are better suited; but doing those just compounds the problem. I don't even have any of the DLC currently; but I imagine it'd be even more of a problem with it.
I assume this is less of a problem going into TVHM?
I always ended around level 34 for the first play through (doing most, maybe not all side missions). Tvhm starts at I believe 34 maybe 32 but it seems like you level slower and the enemies increase much faster. I just killed bunker and I am only level 46 while he was 48. The real fun doesn't start till the second playthrough.