MNblockhead
A Title Much Cooler Than Anything on the Old Site
I think the APs do a good job of supporting the Milestone Leveling system in favor of XP. Which I think is probably a smart move. [MENTION=6563]Azzy[/MENTION] makes a good point above that we're all guessing what is easy or difficult for a new DM, but I would think taking away XP and all the maintenance that goes with it would probably make things easier.
I mean, I've been DMing for a long time and I ditched XP a while back and it's helped quite a bit.
I think that's why the APs largely seem to assume Milestone XP....it's simply easier. "The characters should likely be at least 4th level before they go to this area" is a lot easier to understand and process for a DM, regardless of their experience behind the screen.
I know many long-time DMs and players would hate the idea of having no XP, and that's fine, but to me, it makes more sense for that to be the "advanced" method, and leave Milestone as the default. Especially since the published adventures cover such a large level range.
When I started playing TTRPGs again, I started with the XP model I remembered from the over 20 years prior when I played before. But I wanted more than XP for kills, so I read the DMG advice and come up with a convoluted set of XP rules for solving issues, avoiding danager, exploration, and meeting milestones. I ditched it after two sessions and went to leveling up roughly each monthly 8-hour session so we goto to play from 1 to 20 over two years.
But per-session and narrative milestone leveling aren't as fulfilling for me. Doesn't feel like DnD. Takes away player agency. "You'll level up when I say you do, regardless of what you do." This is why the old gold=xp model was actually brilliant. You can get that gold by killing the dragon or by tricking it out of its lair. And you better have a plan for how you will move it and avoid having powerful groups try to take if from you in transit. The DM built the world--stocked the dungeons. But the players had experience and leveling under their control. They could take more risks and if they played it smart, could level up more quickly. Or take it slow. Or die. My next campaign after CoS will be the new Rappan Athuk by Frog God Games, which is being update for 5e but replaces the XP mechanic with the old gold for XP model.
But I also like (usually prefer) running story rich campaigns. That is why I like the Padron's fractional milestone approach. Leveling is not by DM fiat. The players know that if they explore more, they get more XP. If they interact more they get more XP (by meeting important people, learning important info), if they complete quests, they get more XP, and if they find important macguffins they get more XP.
The XP for kills has always been the least interesting way of giving XP. I don't want to run my games where players XP farm like a bad old-school MUD. God, I hated having to spend hours going back to lower level dungeons killing rats until I leveled up enough to do something interesting. At least with XP for gold you could get over your head, but if you played it smart and AVOIDED the powerful monsters, you could still come away with treasure. Fraction milestone leveling makes it easy to support narrative leveling without taking away player agency.