AbdulAlhazred
Legend
Meh, honestly you can apply any math model you want to the 4e engine. I created a spreadsheet, the Engine Generator, which just takes some basic parameters and plugs them into the core math, so you can use any level bonus you want, any hit point progression you want, any damage progression, and any other types of bonus progressions (items, whatever) and feed them all in. It will tell you the outcome of a generic match up between a PC with expected PC general numbers and a monster of whatever level (IE how many rounds they will fight, etc.).
What I discovered is there's a whole range of solutions which produce fairly viable results where the match ups have desired levels of variance and average durations, and require some desired quantity of resource expenditure (to produce given likely basic lengths of adventuring days). You may also get somewhat different 'banding' (how large level variances can be before outcomes become totally one-sided).
The upshot of it is that wide bands require a lot of variance, low attack success plus high damage relative to total hit points. Neither 4e nor 5e really goes into that territory. They are not really much different. You could pretty much plug 5e's numbers into the 4e engine, albeit you have NADs instead of saves, a few things like that which don't actually change anything. While people SAY that 5e lets you use a wider range of power levels of monsters vs PCs, it isn't really very true. If you take the 30 level band of 4e and the 20 level band of 5e and stretch the later to fit the former, they have close to the same banding.
5e does use a wider range of monster stat mixes though. So, for example it has creatures with MANY more than baseline hit points, or much higher than normal defenses, or very high damage numbers relative to defense/hit points. These get somewhat weird, but you actually COULD do the same thing in 4e, there's no mechanical reason why not. It just gets very hard to assign the monster a level (and I'd note that 5e's CR system really doesn't work for the same reason).
My approach to HoML monsters is that they are like 4e monsters, except sometimes they might have an 'enhanced' attribute. So a certain creature that is a Lurker might have an enhanced damage output, potentially. That makes it a bit higher level than its baseline stats, but by doing this sort of design change in a systematic way, you can fairly assign level bonuses and leverage the engine a bit more in creature design vs 4e. That allows for somewhat less fancy power mechanics on the creature side, which I like.
