Holy priest is far from the weakest on BGs. It is playable in 3s, ofc its not the best (why does everbody want to be fotm in 2020), i play it and its rly fun, but the greater heal build is abit boring. Holy is sadly not available for pushing 20+ key because its low dmg output, if that is your case, otherswise its exactly as good as all the other healer on lower keys.