Quiz time: Between Rogue and Sorcerer, which class is better at using a divine scroll, such as of Heal?
In D&D, the answer is Rogue, because he has the UMD skill to read it. Even if the sorcerer did manage find the skillpoints to train it, he'd be limited to half ranks and his charisma won't quite cover the gap.
But in DDO, the answer is Sorcerer, by far. Both of them can manage to cast the scroll, but only the Sorcerer can spend AP to get from 25% to 55% more healing out of each one.
This is an inversion of the intended relative abilities of the classes: Bards and Rogues should be the best at UMD, as they're the only ones who can get complete ranks. (And bards should be on top, because they'll tend to have charisma). But it turns out that Wand Mastery can make any of the 5 classes who get it better at UMD tasks than a Rogue is. We can be sure that the sorcs and wizards who train Wand Mastery don't actually want it for offensive wands, and unless they're WF they probably don't want it for items with spells of their class either.
It makes little sense for a Sorcerer to have an enhancement that works on Cleric spell items, because he's actually less-good at divine magic than a Rogue is. I wouldn't suggest nerfing those enhancements though. An obvious fix would be to just allow Rogues to train Wand and Scroll Mastery, although that would feel a bit weird because it seems like a caster thing. Here are two alternative approaches (all of which could be used):
1. A new special ability, part of the same list with Imp Evasion and Crippling Strike, which offers spell-item amplification (and probably some other bonuses)
2. Rename the Mechanic specialty to Mastermind, and in addition to the current (unimpressive) benefits, give it +1 (per tier) to wand/scroll DC and charisma skills, and +15% (per tier) to wand/scroll effect.