AbdulAlhazred
Legend
So, HoML actually does all of these things in some measure. Its pretty much a 4e engine, at least that's the starting point, and so you have bonuses, but they ALL fall within 1 of 4 types, level, ability, proficiency, and permanent. Notice, NONE of those can vary based on the situation at the table! That is to say, they can to the degree you could pick up a different weapon and gain/lose a proficiency bonus, and permanent bonuses can be 'keyed' any way you want (IE apply only when certain tags exist on the target of an attack, etc.). Still, the bonuses cannot stack within a type, so AT MOST you can have 4, and level and ability bonus are pretty cut-and-dried at that! (I guess an item could change your ability, etc. I mean anything is possible).There's two I've seen.
1. Just reduce the number of different types of bonuses. That way its still possible to hunt for a few, but it doesn't turn into the 3e stack-a-million-bonuses thing. This is the PF2e approach.
2. Diminishing returns. Shadow of the Demon Lord has what are called boons and banes. A boon adds +1D6 to the roll; a bane subtracts -1D6. You can have multiples of any of them but you only get the best. So if you've got three boons on your attack roll, you roll the D20, roll 3D6, and add the best of the D6 rolls to the value. It means its still somewhat useful hunting for multiples, but less and less so.
Edit: And to be clear, I don't really care how smoothly it works; it produces a result I don't like twice over; it makes only bothering with the first benefit what you do, and then it makes it matter too much.
Again, if you want to gain different sorts of results, use different powers, spend power, leverage practices (which change the ability score and skill that are relevant) etc. Players can have a big effect on how well their plans turn out, it really IS a tactical game, but you will never be sitting at the table trying to figure out all the bonuses that are in play, it just won't happen. My philosophy here is a very strong "invest in the things that will make the game play most appealing at the table." This is an ethos that should be recognizably derived from 4e's design philosophy. Even as complex games 4e and HoML are rather easy to play at the table, especially for the GM.