I am actually playing with a inf/cav shielder hybrid, 15/21 6Ath 6Riding 7WM 5PS 5Shield; I usualy get good scores (I even play with 200 ping all day every day) so in my opinion Shielder is the easiest class ever, at least for those who have high delay as me.
The best advices I can give you to play shielder properly are:
_ALWAYS avoid weapons wiht bonus against shield, those weapons are aimed to destroy shielders, it has no sense to try to counter them with a shield.
_If you are going STR shielder try to get a fast shield or weapon(Elite Cav Shield + some blunt weapon or Heavy round shield + scotish sword or somthing like that)
_In my opinion if you are going Shielder NEVER waste points in IF, you have a fucking shield why would you want more HP?
_Also, try to go medium-light armour; shield reduces your swing speed a lot, heavy armour does too.
_Don't go full Shield(Ability), only get enough point to use the shield you want, it is worthless to put more than you need.
Sorry about my bad english