30MS SIS-A00 TIASHA (Dahlia Wear) [Color B]

Bandai at some point decided to release updated versions of their original three 30MS girls, that being Color A Rishetta in the Freesia version, Color B Tiasha in her Dahlia version and Luluce in her Lily version.

They feature matte skin and an updated torso and leg construction, as well as updated hair and different expressions from their original versions, with slight equipment differences.

Aesthetics:
I don't have the original Tiasha, so I might be missing a couple of things, but the biggest differences are the bare legs but covered thighs, bare arms and a bare midriff. Instead of the folds on her old 'thigh boots', she now has a couple of flared folds on her hips, in between the torso and the hips.
I don't know how small the original Tiasha is, but this is definitely one of the smallest bodies. She uses Color B, fair skin.

For whatever reason, instead of making her chest compatible with other models, she has a tiny non-replaceable cleavage, with a removable cloth styled tank top.
Her included equipment has been overhauled and while it is reminiscent of her old wings and frills, the wings are now more prominent, the headband has two colors and the frills are replaced by plates that slot onto 3mm pegs as gauntlets, thigh covers, shin guards or whatever you prefer.

As mentioned, the skin is now matte instead of glossy and the hair is more detailed.

Mechanics/Compatibility:
Tiasha now has the modernized 3-piece legs, forgoing a double knee bend for a single, that looks more natural from the front and enabling you to swap out the shoes (the soles have cute little bird designs on the bottom).
She also no longer uses the various multi-peg armor parts, that her predecessor used.

As mentioned, her chest doesn't come off, but her torso does come apart at the middle, enabling you to swap out the upper or lower torso. That means the Sestieh G-cup on-a-short-stack-body dream is entirely possible.

As far as compatibility goes, she has normal sized face plates, the same removable hair tab and the usual two 3mm hard points on her back and lower back, without the rectangular tab.
I tried replacing her hips to bare ones, but the ones she uses are very small. Also, be warned, the hip pegs seem very tight.

The energy blades on her swords use 3mm pegs, making them versatile effect parts. Similarly her backpack also uses 3mm pegs and hard points, as well as her wings, making all of that especially compatible with 30MF armors.

Equipment:
3 Face Plates - Confident Smile, Raised Eyebrow Shout and Half-lidded Unimpressed Frown
3 pairs of Hands - Open, fists and holding hands
2 Oval Armor Plates ("gauntlets") - 3mm hard point on the inside and outside
1 set of Wings - Two small red wings, two larger black wings, one backpack to mount them onto
1 Headband
2 Sword Hilts with 2 Pink Beam Effect Parts
1 pair of spare Bare Shoulders parts
1x 3mm Peg Extender
1 set of the usual Ring Parts in desaturated red

Conclusion:
I think maybe Tiasha continues to be the weakest of the original trio, being a little too neutral and unspecific looking, with her flight equipment. If anything, she sort of looks more generic now, albeit a little less clunky.

The lack of a proper chest-swap is a little odd, but the equipment is versatile. Despite her petite size, she is not so slim/small, that she could use the 30MP 'Bocchi' legs, which are far slimmer.

The improvement on the older type, is largely aesthetic, as the old limbs had better bends and more hard point options, but offers more segmented options, such as replacing the feet/shoes separately from the rest of the legs.
I would say that the older model, based on the other ones that I do have, is still perfectly viable and still a useful model.