I've found that what's more important than what's effective on paper about a mech is the feel of it. How well the mech "suits" you as a pilot, really, because if the mech doesn't click with you and your playing style then chances are you'll do badly even if it _should_ be a good build, and vice versa. For me, the Panther just clicks the right way. It _feels_ right when I'm running it. It feels and reacts the way I expect it to so that I don't find myself fighting my own mech. And like you, Bishop, I'm no natural light pilot. I'm far more comfortable in a Griffin or Wolverine than in a Jenner, so the Panther tickles the right spots on my mechwarrior-brain.
I love the damn thing, and I run my 10K pretty much built like the one you posted in the OP. 1 ER PPC, 2 SRM4, modules for ER PPC range and cooldown as well as Radar Derp module. Cue jumpsniping. Almost reminds me of the ol' pop-n-drop from the BTech MUX days back in the 90's which also used real-time combat where you'd go prone in cover to disappear from the radar scan and then, having locked a target you knew the position of, you'd stand, fire and drop prone again in quick succession, hopefully never being spotted by a mapscan before you'd dropped out of sight.