I am going to be running a 5th edition campaign soon. So I thought I'd better actually familiarise myself with the rules - that could come in handy. To this end, I abused the print facilities at work today to get my hands on copies of the free "Basic" versions of the rules, as well as a few bits and pieces from the SRD. (I think WotC are to be commended for doing this, from a long-term growth perspective.)
I am an extremely lazy person, and as I get older I have less and less patience to learn new systems. Luckily 5th edition is still recognisably D&D, and probably more recognisably D&D than 4th or 3rd edition were to me. That said, there are some big differences from what I'm used to (which I call BECMI, but is really just Red Box Basic, because I use none of the optional rules from the Master's set). Here's what I've noticed so far:
1) They made it really hard to die. I mean really hard. PCs in 5th edition come as close as dammit to having plot immunity. I'm not sure if it is harder to die in this version than it was in 4th or 3rd, but listen, in the games I am used to running, if your hp falls below 0 you are finished. This negative hit points and death saves business is going to take some getting used to.
2) Monster stats are mercifully brief in comparison to 3rd or 4th edition, but still seem long to me - you have to work out the ability scores of monsters and keep track of modifiers? I'm going to have to think up a way around that if possible.
3) They've made hit points extremely abstract in that they basically refresh on an hourly basis, especially once PCs have gained a couple of levels. I have no problem with that in theory but in practice I feel it may result in odd circumstances within the fiction (DM describes combat round: "The orc stabs you in the chest, almost killing you...." One hour later, after the fight and some rest: "You're fine now.")
4) The spell lists seem like they have been blandified a bit, or is it just me? There don't seem to be as many spells as in PHBs of yore, and those that are there seem less interesting. But maybe I am spoiled by the extensive combination of spells I'm used to, which draws from the Rules Cyclopedia, AD&D, and quite a lot of other 1st and 2nd edition source books.
5) Because this post feels picky and negative, a positive thing: in the early variants of D&D which I am used to playing and running, character start off with brutish, miserable and usually short lives. They are pretty pathetic and the early stages of a campaign are tough. I prefer things that way, on balance. But there is nothing wrong with a bit of variety, and 5th edition looks like it will be a nice change in that PCs will start off competent and capable. I am looking forward to something different in that regard, as well as the more tactical, war-gamey feel that combat seems to promise.