I don't really find the Tax Collector that useful. I have played the game a half dozen times or so now and there always seems to be a way around the tax collector. There are plenty of spaces available in a 4 player game everywhere on the board.
Magisters are way to powerful at the start of the game to just keep in your hand. If you are going last and it bothers you. Put your magisters in your second hand and just take 5 courtiers. Remember turn order is first done by the number of cards left in hand, then whether or not it's a magister.
Personally find the Cleric a lot more useful than the tax collector.
I think the Tax Collector is good for making it harder for other players as money can be quite tight. However, it doesn't help you a lot to get money (if that makes sense). In the few games I played, a Tax Collector (or even 2!) on the Planetarium or Academy helped to gain the majority for the player who bought 2 of their scientists using a TC.
As for the starting bonuses, I haven't played it often enough, but an extra token for the 4th player seems about right. Even in a 2 player game the 2nd player receives an extra recruit; being last in a 4 player game is far worse as you pointed out.