I wouldn't compare Senran Kagura's 3ds entries to Dynasty Warriors and such because Koei makes a more open 3d battleground, and the fighting is more strategic in that positioning is more important.
I'd say it's more a faster paced streets of rage, or Scott Pilgrim vs the world, or something like that, because it's a side scroller that rewards fast reflexes and is pretty hectic, and I don't know what else to compare it to.
Senran Kagura Burst does get challenging *Mutters about the white/red kunoichi, and the poison blowers*, but I haven't played enough Deep Crimson to know how it holds up as the enemies, and fighting style has changed a bit. Odds are, though, if there's a challenge, you can grind a bit, and overcome.
I do think it's an excellent series, perversion aside. Burst was well written, gameplay was great, and it basically had all I could ask for. I'm sure deep Crimson will hold up just fine.
I can understand any shame behind the purchase, but to hell with that, go have fun!
I guess some warning. As great as the series is, er, I'd play with the sound down, or headphones as far as playing around people. Almost every foe so far is a woman, or a doll, so the screams of a dozen girls as you mow them down might garner attention from others if overheard. The levels of boobs, and their jiggle that put DoA to shame are present. In fact I think they're higher in Deep Crimson over Burst. It's loaded with "fan service" like a photoshoot mode but I think it's handled better than in most games. I mean it's so blatant, and by design that you know that you're getting. the fan service is a feature instead of being wedged in to a story that it seems out of place.
Anyhow, I hope you enjoy the game, and I recommend it to pretty much anyone. Kinda strange seeing something like this on a nintendo handheld as it makes bayonetta look tame, but I'm glad it's there.