Aromatisse: C-Tier or D-Tier?: In my opinion, it's a D-rank pokemon. First of all, it needs trading to evolve. Second, it depend a bit on TMs, as its only good level-up moves are Moonblast and Psychic. Also, it has rather average stats, and awful speed. It does help against Korrina and Drasna, but usually it'll be too slow to be worth it, and Aromatisse gets beaten in many other battles, like Team Flare, Malva, and Wikstrom.
Pansear: C-Tier or D-Tier?: I'd put it in C-tier. It can be caught and evolved pretty early, and if you don't evolve it, it has a nice learnset, with moves like Incinerate, Fire Blast, and Crunch. It also gets moves from TMs, like Grass Knot, Rock Tomb, Shadow Claw, Low Sweep, and Dig(although they are not mandatory). Pansear/Simisear help against Viola(Surskit sucks, though), Ramos, Clemont(if you teach it Dig), Valerie, and Wulfric. Against the Elite Four, it has bad match-ups against Siebold, Drasna, and Malva(to an extent), but it helps a lot with Wikstrom. It's OK vs. Diantha too.