Talking about what might happen in two years is a bit pointless. What we have right now are two better full backs than Walker, and we need to focus on improving this year and bringing in some forwards to give us a shot at the top sides for next season. Longer term we should be looking at kids who are round and about first team already - Sinfield, Simpson, Edwards etc.
Walker shouldn't be OK with playing reserves or on loan - he's still young and ambitious and will want to play first grade every week. I genuinely wish him well but have never quite understood the hype.