Ggglygyedit - just thought of this: really popular competitive games like SC2, Dota, LoL, CS:GO all have dedicated spectator modes where spectators can check things like gold advantage, overhead maps, food totals etc...
TF2 lacks these features so spectating is less user-friendly.
Oh, yeah. Spectating an FPS is hard already but TF2 sucks in terms of specatating. bluee is saving us a bit with the outlines, ubercharge stats and DMG/Kills stats but there is only so much that can be done to mod the game. There are so many things that would really add to the game. Sadly Valve doesn't care.