I would just do a full respect on your main and save the gear.... Won't take long to level 2h etc at high levels. That way your not investing all the time into a full on new tool.

I hear a lot about stamplar being inferior to magplar as DPS and I really think it's a lot more of a L2P issue. It's much more powerful in magicka in many ways, but in general is screwed over in the sense most stam builds are.

Stamplar certainly lacks a few things: an execute and class support. Originally, I played my stamplar with a dw/2hander. I've since learned that spamming executioner is actually a DPS loss compared to continuining a biting jabs + PoTL rotation, and since then I've only used 2h for PVP. In PVE, however, DW front bar and Bow back bar (for dot application) works wonderfully on a stamina templar.

Still, the burning light proc passive from the aedric spear tree, and the critical chance passive from the CP tree tends to be where you'll get most of your dmg from as a stamplar. Because stamplars are incredibly crit based, this is also what is pretty much screwing them over right now, as burning light is spell damage and scales off spell pen. A good fix for that is to run sharpened daggers, but it's still a set back. The precise strike passive in the CP tree, which stamplars also heavily depend on, only grants you half the percentage of what you actually put in. So from the get go, your primary source of damage (jabs) is pretty much screwed over; they would be MUCH more powerful than they already are if burning light was physical damage and if precise strikes actually scaled correctly. But if you play a stamplar well, you can still easily outdeeps a magicka build. PoTL is extremely powerful and important to reapply in between rotations, and with the TG patch, it's going to be even more powerful. Scorched earth and poison injection are also powerful dots to put on the back bar that also increase DPS a lot, especially if you have a maelstrom or a master bow at your disposal.

In terms of sustain, I feel both magplar and stamplar are cost-heavy. As a redguard stamplar that gets back stamina on every melee hit, I've never felt the starving for stamina to be as hard as some friends of mine who play imperial or wood elf and constantly mention the lack of sustain stamplar has. But magplar also suffers a lot from sustain issues, even with channeled focus and siphon spirit going. On single target fights like the possessed mantikora, my stamplar ends up being a DPS loss simply because of the lack of sustain and the inability to repentance off of anything. Even with shards dropping, majority of the people I raid with are magicka builds and so shards drop sparingly and for the tank. However, if stamplars had a sustain skill that didn't depend entirely on repentance, and if more stamina build support was provided in these situations, a stamplar could easily match some of the more magicka builds out there.

At any rate: magplar is also a really good choice. I know people that run a build similar to your magplar, though I also know a lot of magplars that run dark flare spam with purifying light and kena procs. It is an insanely powerful combination, but also a very, very expensive one that is hard to maintain without a support healer. In the end, I agree with what most people say, in the sense that you should just try out both playstyles and try out what you like the most!