First of all, I'll start with the fact that while Shcherbakova indeed has very small jumps, Tarusina has at least as small jumps herself, if not smaller. Therefore, I really don't know about a potential GOE advantage. Although, she does tend to have neater landings on Salchow.
This second point is also important - Even more important, I would say. A 4Lutz does not replace a 3Lutz. In fact, Shcherbakova does 2 3Lutz in addition to it, while Tarusina performs only one. If we compare their potential layouts using what Tarusina had last season(ignoring backloading because I don't know how Tarusina would backload, though I doubt it'd be more than Shcherbakova):
Shcherbakova:
4Lz
3F-3T
3S
2A
3Lz-3Lo
3F-2T-2Lo
3Lz
Tarusina:
2A
3Lz-1Lo-3F
3Lo-3T
3F-2T
3Lo
3S
2A
Shcherbakova BV assuming UR 4Lutz that she falls on:
3.32 + 9.5 + 4.3 + 3.3 + 10.8 + 8.3 + 5.9
Total: 45.42
Tarusina BV:
3.3 + 11.7 + 9.1 + 6.6 + 4.9 + 4.3 + 3.3
Total: 43.2
So even if Shcherbakova falls on an underrotated 4Lutz, she'd still be pretty well off. Although Tarusina could of course make up for the 2.22 points in GOE.