I agree 100%. My clarification would only be that some mechanisms (and I cannot remember specifics) allow the player to have more certainty than the PCs would have access to. Again, not a good or bad thing, just is. Secondly, for a DM and player to simulate a common/shared feeling of knowing that there's no way in hell you could jump across a 2m wide hole but could jump over 1m hole most of the time requires very simulationist guidelines AFAICT, which generally speaking, is what I understand is what 4E is moving away from. So depending on how many climb, jump, etc. guidelines you add, the more you're moving away from that 4E paradigm and into complex 3E-style rules. Again, not "good" or "bad" but something that Mearl really needs to touch upon IMO.