Learn to love your level designers!

There is no element that goes into creating a game that is so dependant on the people doing it as level design. Yes the programmers have to make the game work as you intend it to: movement systems, combat systems, AI etc but you play the prototype versions to make sure things are going as you intended, and can tweak that as needs be. If you want a distinct style of art for the game then as long as you have an art lead who understands your vision and can implement it and can take constructive criticism then you're safe.
But when it comes to creating the physical game levels the level designers are possibly the only people on the team whose individual skills will be so utterly evident to the player. So if you have someone whose levels are consistantly poorly made, show no imagination and are dull to play then what do you do? Lose them and spread the work around everyone else? That tends to be what happens (if the boss is brave/good enough) but then the others on the team become stretched and overall quality can suffer. Ideally you would keep them on, but make sure someone was keeping an eye on their work. Possibly even have the other level designers responsible for “finishing” their levels while the person does the basic blocking in and learns how to do better layouts.
They are such important people as you can have the most incredible game design ideas, the most amazing story and characters, but if the game levels are boring then it is the ultimate definition of a missed opportunity.
Me? I'm a bit of a control freak, and knowing how vital level design is I can't help but have my hands full into that side as well. I typically come up with level designs and concepts for the games I design anyhow as I can picture and play the entire game in my head, so it all comes together that way.
What brought this rant on? Finished Painkiller today (I know 🙂 I'm catching up on some old purchases) – superb fun game overall, but with one of the worst opening levels I have ever played. Probably fits the design brief perfectly, but zero thought has gone into the layout and no imagination into the visualisation of it. Almost put me off the game entirely.