TLDR: general rule of thumb if DLC doesn't impact main game and could easily be standalone contained games, its optional and i can ignore. If it does impact main game or story interests me: get it. But doesn't explain the TW/ 4x stratgy game issue or the sometimes BS selling preexisting character roster in fighting games.
i think thats where i'm at as well. If a DLC does enrich a game then i have to get it as part of the main game. In most cases i usually wait for a sale or whoever is selling it cheaper (isthereanydeal.com etc) and snag the stuff i want.
The problems really begin when which ones are going to enrich a game and what is side tat. DLC costumes i ignore, exp/resource boosters and cheat codes can go to hell; if you can accomplish something by playing the game, either your game needs to be rebalanced or you're trying to fleece the rich and impatient. Extra weapon's DLC is questionable and i ignore them as well.
So... What will i consider? Additional story/features content that impacts the main game certainly. if its side tat like AssCreed's Syndicate jack the ripper DLC on hindsight i could easily ignore as it was its own contained area, neither the main game or DLC impacted each other and didn't really add much to the story. Hell, i would have said it could have been a standalone piece.
Now that i mention it, that's probably the main crux of of the DLC; does the DLC stand up on its own as a contained standalone experience? if it is, i say that i would probably ignore it. I had hoped to get Ghost recon wildlands Gold edition for all the DLC until someone told me that the DLC was seperate from the main world and their own contained stories and areas and was marginal (cosmetics) so i just got the standard version and kept with that. Same with Blood Dragon. AMAZING DLC but completely separate from FC3 and you could ignore it but as a self contained experience, well worth the purchase.
Of course i'm being a bit vague as there are other criteria's etc as to whether i would have to consider deeper. Frank west rising DLC isn't long or particularly great and i would have regretted buying it full price, but the story is compelling and certain added more to the story as i recently mentioned felt like the Overtime chapters of previous games. But as someone who doesn't play fighting games? again depends on the amount of content. if its cut the roster down to just 4 out of the original 15? Sod off i'm ignoring your game. if its all the classic ones + others to round off the roster? i can tolerate. So stuff like injustice 2 is ok and i'll let is slide with MK but only just.
But what about strategy games? v Crusader Kings constantly adds additional features all optional yet enriches a game significantly and i would have been compelled to get them. Thank god i don't. but for other games like Two point hospital etc? well... different story. i would like to get it, but all that DLC suggests additional content that might be good to have, but i want them all in one neat package so i wait... and wait... and wait...
TW is even worse. i want to get Warhammer 2 but all that DLC makes me pause. I get that i probably won't play all those factions, so i COULD save money and not buy them as i won't play them anyway. At most i'll play it 2 or 3 times and stop and yet... the option to have it there is enticing. But again i pause and wait. Who knows, maybe there will be a Warhammer collection and i bag the lot.