at 4|5 i wouldnt call it weak. if you want it weak it would be in the 1|1 to 2|3 range. with devour and considering it is poisoned, its hp growth would be very limited (none, actually) so it will be a maximum of 1 less than whatever you put on the card, assuming it eats every turn.
scavenger is another way of doing that, but it will have different mechanics of staying alive, sometimes it may grow faster and stay alive longer than with devour (i believe there is a pvp deck with fractal sparks combined with vultures that did very well in a tournament recently)