Silly question but I'm a "buy one game and play only that for months" type of person. Thanks!

If this is your first time playing, play without the DLC. Activate the extra characters, but leave Crimson Court and Color of Madness off. You can actually activate the DLC at any time after you've started a game, so play until you're comfortabler and then turn them on/

I would not even turn that on, just use the base game (to have more fun later).

I agree.

No DLC to start with. Just play the base game. The bulk of the best content is in the base game, and you'll probably appreciate the added content of the DLC more if it is in fact added later rather than there to begin with.

I would suggest playing with the DLC on if you've already paid for it. The blueprints that are required to build late game class halls are dropped by bosses; if you play through the base game and then activate the DLC afterwards you will end up farming for them. If your plan is to play without the DLC on your best experience is going to be starting a new game once you plan on using it. The only downside to having it turned on at the start is your heroes getting afflicted all the time and making it hard to keep them fit. This can be solved by never spending any money healing your party for any reason and either letting them die or kicking them out once they're too far gone. If anything, playing with the DLC on for your first run will give you a better sense of spending your party like resources and not getting caught up in their well-being.

Yeah, devs destroyed their game, it was beautifull before the DLCs. Now we're compelled to dismiss our toons, I liked keeping them ALL, now it's impossible, the game has become boring.
So, DON'T BUY ANY DLC !!!