I think
@davek has got a point here tbf. Dowell isn't going to learn anything playing against players who are nowhere near his level of talent. In fact, very few players in the Prem are as naturally gifted as Dowell.
Dowell would add exactly what Sigurdsson adds, not counting the experience. In fact, probably more. He can take set pieces because of his technical ability, but in my opinion he has probably a better X-factor player than Iceland. Obviously he would have to be eased into the team, but
Dowell should have been in the first team squad.