seeing all the collisions already, should it be a mandatory piece of equipment/

or will it make players more prone to challenge at headed situations?

It won't make a difference.

Most footballers have their brain in their leg.

And some their pants.

How would they do headers then?

I actually think Cech has an unfair advantage with his head gear. If he's not fit to play without it then tough luck.

Still not decided on those face masks. They're also a little dodgy.

Why is that?
What about Edgar Davids' glasses, Terry Butcher's bandage and Jason Lee's pineapple?

I wouldn't count a bandage as a piece of equipment.

Players with bad eyesight aren't allowed to wear glasses (at least I don't think they are). I'm not sure of the rule that allowed Davids to wear those glasses.

Cech's head gear is a padded piece of equipment verging on being a helmet.