Weapon Effects Make No Sense

With the announcement of the upcoming improvements to the MTX store, I felt I should point out a couple of tweaks that the MTX system itself could use.
During the recent weapon skin/effect sale I caved in and bought a few things, and I have to say I'm disappointed with my purchases. There's no consistency between how different skins and effects work; I bought the Seraph dagger skin thinking I could use it on the claw I'm using since all the other dagger skins work on claws, but for some reason that one doesn't. Ideally, any weapon skin should be usable on any weapon that uses the same number of hands, but at the very least which skins work on which types should be consistent.
I also bought the Infernal weapon effect, which looks great, but I look silly using it because I'm playing a dual-wield build and it can only be applied to a single weapon at a time. This is ridiculous; I understand that PoE is free to play and the development costs need to be paid somehow, but the MTX prices are already severely stretching the limits of what can be considered a microtransaction, and now you expect me to pay double just because I use a second one-handed weapon instead of a shield or a two-hander? Weapon effects should all work the way the ones earned from league challenges do, applying to both weapons if the opposite slot is empty.