if you have a support you can easily do astral without a heal

also all your dps do around 25% more dmg and can survive themselfs you you buff em selfhealing and last but not least you do pretty deacent dmg as supp

so my advice is go engi as it is the most flexible class in my eyes (bard is pretty similar but i prefer engi)
btw healers are actually not rrly that much needet in allods

you barely see em in battlegrounds, in high end domi you have 1 heal in a 6 man grp and in raids you usually have 2 for 12 ppl
tanks the same no need for tanks in pvp and in raids you have max 1-2