I wouldn't say that in general pearls are more or less sensitive to release variations. In my experience that's been more of a characteristic of a given ball whether it's solid, hybrid or pearl.
A pearl could open up the lanes more for you, especially once the lanes start to break down. Typically I'd expect more length and better recovery on the backend with a pearl, but cover/core strength also play into that as well as the oil pattern. I wouldn't hesitate to add a pearl to your lineup if that's your concern. I'd much rather have some variety in the bag rather than all hybrid, or solid or pearl covered balls. You never know what you match up with until you try it.
Not sure what to tell you on the Optimus vs Fusion. Like others have said, I think they're close. I'd guess the main difference is in the reaction shape. I have a 3yo Marvel Pearl(same cover but different core than the Optimus) that I "replaced" with a Fusion and they're not that far apart but they are different.
Comparing the Marvel Pearl to the Fusion, on a house shot I'm about 2 boards with my feet and 2 boards on the lane left of where I am with my Marvel Pearl. On a sport shot it may be more like 4 and 2. I do think the Fusion can handle a little more oil but that gap may not exist with the Optimus. Fusion is definitely stronger on the backend but if you hit the dry with it too early it will read much earlier than the Marvel Pearl. Marvel Pearl may be a touch longer but more smooth(but still strong) on the backend. So I'd say the Marvel Pearl is slightly more controllable on the backend. I'd expect a similar reaction with the Optimus as the Marvel Pearl, it just might be slightly stronger overall than the Marvel Pearl.
Kind of going off on a tangent about release inconsistency here:
Not knowing how consistent your release is, it could also be argued that if you're seeing sensitivity in a ball's reaction that it could be due to the ball's surface and not release variation. If you don't like a ball's reaction consistently over time I wouldn't hesitate to change the surface. Surface changes can make a huge difference.
For example I've never met a Storm pearl I didn't like but hate the box 1500 polished finish most of them come with(Marvel Pearl, Optimus and IQ Fusion all come like this). For me that surface hooks too hard off the dry and doesn't hook enough in oil giving me an over/under reaction. 9 times out of 10 I hit them with a 2000 Abralon and I get a great reaction then - I had to do this with both my Marvel Pearl and Fusion and various other Storm 1500 polished balls over the last 6-8-10 years. If I'd never tried changing the surface I'd probably be saying most of Storm's pearls are too sensitive and to stay away from them, and I'd be missing out on what I think is some great equipment.
