i've never said the job he done was average or anything. i only feel he stagnated in the last couple of seasons where we kept getting into positions to improve i.e. qualify for europe and we just didn't. he kept bottling it due to his management skills only. nothing to do with net spend or the players he had available.
i think the fact that martinez has shown that we can be improved under the same circumstances means that he did hold us back in a way, the same way, as you say, another manager would have made us worse.
stagnation is holding back, because it's not achieving the maximum potential.