The general consensus from top m+ tanks is the following (so far) in S2 for M+:
Guardian Druid>Prot Warrior/DH>Monk>Pala>DK
What sets Guardian druid apart is that has 30 seconds of invulnerability via their leggo which allows pulls no other tank can do… they are also extremely tanky. If playing NF they can call for trees, go into Boomy form and convoke for massive damage. Their downside is that they are boring AF to play and have low Single target dps outside of convoke.
Warrior, on the contrary, is super fun to play. It’s high paced, has a lot of buttons, and is really satisfying to play. The new reprisal legendary has enabled nearly 100% uptime on shield block, which is the best physical mitigation in the game (make sure you craft if on feet). Warrior threat gen and aoe is great, but they lack single target dps (but they’re on par with bear).
Warriors downfall is they have minimal self healing and are weak(er) to magic damage then other tanks. They specialize in mitigating damage vs self healing. As a result, you need to know the types of damage you’re going to take in each scenario and have a strategy planned to cover your weak spots. However, once you understand what mobbs are going to wreck you you can cover with other defensives and healer externals. For this reason, warrior has a higher skill ceiling then other classes.
Spell reflection is a 20% magic DR + reflect on a 25second CD. There are many abilities that are completely nullifyed by spell reflect. For example, Peircing barb from hakkar, Reaping sycthe from the last boss of TOP, and the slam from the last boss of DoS. You can literally mitigate 100% of nearly half of these abilities - and then cover the others with demo shout (20% dr on 45 sec cd), trinket, or wall. You can also reflect tons of mob abilities for big dps. In spires, you can reflect etherdiver casts. Pull -> shockwave -> spell reflect all their casts at once -> enjoy 30k dps on the meters.
So to answer your question, yes, I’d definitely recommend prot warrior. Warrior was the king tank in S4 BfA and lost all the things that made them OP coming into SL. Community perception was they are a trashcan (and they were at the start of SL). Since then, they’ve had multiple tuning passes and have had the introduction of the reprisal leggo which has thrusted them up the M+ tank hierarchy quickly. But they’re still flying under the radar because they were in such a bad spot at the start of SL.
Edit: About the kyrian/NF question.
I play kyrian and the 1 min on spear means it’s up every pull. It accounts for about 10% of my overall damage and is excellent for threat gen.
NF does more damage (if played correctly)) and is on a 1.5min CD, so it’s up for every-other pull or so usually.
Personally, I prefer kyrian because of the shorter CD, comparable dps, and most importantly, phail. Phail is huge and allows you to remove all sorts of nasty dots in m+. Warrior has ton’s of mobility so soulshape is not needed at all.
I’d recommend Kyrian, but NF is a strong alternate. Neither are going to make or break you.