FormerlyHemlock
Hero
I get it. I esssentially hit the same wall. I was converting everything , and at a certain point said "why bother?". I love 5th, but I dont use the AP/long, save the world yet again stories WOTC is putting out for it, so Its just easier to take adventure X and run it under whatever system it was designed for.
On the subject of a/d- I transported the idea into Castles and Crusades back during the 5e playtest. Castles and Crusades' "prime" system has always bugged me, but I love how easy it is to houserule the system (I prefer to add to, rather than subtract when it comes to rules) and convert products from 0e through 3rd on the fly in about 2 seconds (flip AC, figure out whether monster saves should be better with physical or mental abilities-all the other math is fine-as is) So I simply dropped the 12/18 challenge base, and set all challenge bases (think DC, which then gets modded by the level/HD of threat) to 15, and characters who had that ability as prime got "advantage" on the roll. Works awesome. The PCs are a tad more heroic than with the original systemwithout a big power increase AND they do slightly better on nonnprime checks (where as written, non prime checks have a very low chance of success- something that many C&Cers think is a bit too rough). So yeah, fiigure out how you want to incorporate it into 1/2e. Its totally worth stealing!
I understand where you're coming from on this. I spent a while playing GURPS: Dungeon Fantasy, trying to convert AD&D or D&D content to GURPS. It never really worked out, but it did prime the pump so that when 5E came out I was open to playing it.
Adapting stuff across game systems can sometimes distort the material beyond recognition and give an unsatisfying experience. Personally, I'm currently reasonably happy with 5E (one big factor: even though I hate how combat-oriented 5E MM stat blocks are now, I at least appreciate having Str/Dex/Con/Wis/Cha stats for everything instead of strictly just Int) and my players know the system; but it wouldn't shock me if I at some point returned to AD&D instead. AD&D does have a superior magic system, especially for priestly magic. (Simultaneously more powerful and much more fragile: no casting while moving, for example.) The main downside of playing AD&D would be: 5E combat is more tactically intricate. AD&D has some cool stuff you can do with called shots and Complete Fighter's Handbook-type stuff, plus some specialized weapons; but 5E fighters have grappling/pushing which is generally more effective due to the way disadvantage works. If I were to play AD&D I'd feel somewhat compelled to extend martial combat to include some 5E stuff like the effects of being prone, behind partial cover, or out of visual range. In short, bell curves are more interesting than linear d20s, and 5E has better bell curves, as well as a more interesting action economy.