Noble and Spade have promised to me in private that whoever loses the poll will also buy a videogame for every single user who voted against them in the event of a loss, they're both such nice guys.

Edit - Free Neptunia!!!

I do not know but I am at level 68 and the world bosses can still one shot you.  Also at level 68, the 4th tier opens up and going through that dungeon I probably died more there then I have throughout the whole game.  I highly doubt you will be OP in Tier 3 because just the nightmare dungeons you can come across multiple enemies that can put you to sleep with one or two hits.  

Before I beat the game, I was almost level 60 because I did pretty much every side quest I came across until none showed up on the board anymore.  You really do not gain that much experience in Tier 2 and you only really get to customize your build when you unlock the Paragon board at tier 3.  Even then, you need to farm for unique equipment in order to really get your build powerful enough to even touch Tier 4 unless you are super grinding all the time.  Even after you finish the game there is still a lot of quest that do not open up until you beat the game and then there is all the end game content to muscle through.  I think I have had more fun in the end game then I did during the main quest line.

Lies.