Fernando has a really well-made name, for one :3

Also, Mandy appearing so much is one of the reasons I don't feel so attached to her. We see her tons anyway. Topaz needs more unaffiliated NPC storyline characters. Mandy feels kind of generic and hard to detach from Bugsy.

The reason to switch (my bad with the positioning of Abaddon) would be to give trainers a breather between Hanzo and Fernando. Otherwise it doesn't really change much, even geographically (you could even imagine Hollowlog's log as having been something akin to Roothaven's tree). It certainly isn't very much trouble to make the switch.

@Zenith: The thing is that what you are trying to do IS a big upheaval. If we change Aurora Beam, then all the reasons that apply to Aurora Beam apply to actually creating 12 or so new moves to fill in all sorts of necessary slots for Pokemon. That would require a massive moveset, egg move, TM list, previous gen revamp upheaval that would necessitate a ton of work. I firmly believe that not allowing some Pokemon STAB moves that suit them is a way to encourage diversity. Crobat is cooler in that it's not just "STAB, Nasty Plot, and go". Half of Dusknoir's utility is in that it got Shadow Sneak, but not Shadow Claw. Fire-types must learn to deal with a lack of good Physical Fire moves (Flare Blitz is a step in the wrong direction IMO).

I'm going to preempt you on the Special Lights thing, just to illustrate:

Dolphure: Dolphure's abilities do not require a Light-type STAB. It's absolutely unnecessary. The coverage of Dark (which Dolphure is immune to) and Ghost (which is neutral to both Water and Ice) that Light-type provides isn't what Dolphure needs. It's more likely to run Surf and Ice Beam as a special sweeper, retaining STAB. But what's actually interesting is Dolphure's ability to use Serenade to block all contact moves (almost all Physical moves) then soak up specially or use Mirror Coat. Dolphure's Riptide and Speed make it a unique Pokemon with diverse uses.

Coroona: Coroona is likely UU regardless of any Light-type STAB, though Fire is a good support for Light (SE on Grass and Steel). It still has several excellent support options, with Will o' Wisp, Morning Sun, Charm, Yawn, Purify, etc.

Sirene: I think that it's best that Sirene not have too many options for attacking, it has potential to be broken wide open with what Lapras already has to offer.

Seraph: Has Wrath, needs it for the power in any case.

Slowpriest: Arguably would enjoy STAB, but gets other toys to use such as Enlighten with excellent HP to back it up, and Purify, as well as other STAB to fall back on.

Benengil: Benengil was designed specifically to discourage attacking, as might be evident from the 3 attack moveset.

As for Fault Line, it was changed after that list was made, so it's Physical rather than Support now.