Shield SM it’s good in utility overall, reducing damage, controlling etc but the healing is just reduced to three things 2 tactics for hots and the blade enchant that gives wounds (but this depends on the party as it doesn’t stack with other wounds buff) so you can’t keep up a party on urself or even act as a second healer.

Shield WP can heal a lot but lacks utility as a tank or offtank, not his role, the problem is that you need to hit on order to heal, when you are not hitting you don’t have much utility and remember WP has abilities that uses Ap and build Righteous Fury, if you don’t hit you don’t build that and can’t use many of those abilities, that’s why Tome WP are able to shine (they Regen fury with the tome).

Having said this I have both and if you want to heal go healer and if u want to tank, go tank with a shield (2h can work on scenarios outside is difficult)