I think the way that loans are used has changed in the last 10 years and it will probably change even more in the future because of FFP.
Years ago clubs only really loaned out young players to lower league teams, so they could get first team experience. Now clubs loan players between top league teams, sometimes it is still for development, sometimes it is to put the player in the shop window, so they can maintain their value. Sometimes it is to get a player out the door and off the wage bill when a suitable buyer cannot be found.
Ideally I would only like us to loan players, with a future transfer agreed, but I can imagine that this would mean that we may not get access to some fantastic players. At the time I dont think we would have got Deulofeu on loan with a future transfer agreed.
You can see the loan system as a high risk strategy, last year we had Barry, Lukaku and Deulofeu all on loan, feasibly Barry could have gone to Arsenal in the summer and Lukaku could have gone back to Chelsea and we would have been back to square one, needing 3 players to fill those positions.
But is that really more high risk than;
A) signing none of them on loan and using the youth team
B) Borrowing large sums of money to buy them outright