I seem to be finding lately that I only use eq to fix more things than for actual tone shaping.
That being said, a good preamp in definitely helps with some -dare I say 'warmth', but not sure it is not necessarily that much different from a interfaces preamp in.
But I don't have a shit ton of outboard gear.
I do use a Neve style preamp for my 'sweeet' channel. Vintech X73i that has an EQ. I find that I don't use much of the eq section when tracking. Maybe I should start doing so.
I work more to get the tone right before it gets recorded.