Sorry for the late reply. I’ve been sick this past few days and I couldn’t articulate the words correctly. Imma base this analysis on my experience running him and Kiria as my NCD ranged tanks, but also on how tanking has been evolving lately (without saves).
Story time on how I ended up with FLyon as my NCD tank
My relationship with FLyon has been a bitter sweet one. I blame that juicy 50% DR for baiting me into think he was going to be a ranged BIke (at least for ranged units). And from what I can read, I’m worried that you might be being baited too.
I first decided to invested on him because I was looking into switching to double tanking for AR back in November-December. After reviewing the different options at the time, I decided that the best tank for my needs (someone who could run NCD or a sustained tank, so BIke could be the one running NCD) was either BClaude, HGrima, FIke or FLyon.
Long story short, I ended up with FLyon and a forma Kiria as my AR NCD tanks and from my gameplay, I would say that Kiria outperforms him in most occasions (to the point I switched him to Light, my easiest season, and moved her to Astra, my hardest season).
Kiria vs FLyon vs YLyon
Side note: omnitanking or specialized tanking?
Before going deep into comparing them both, I have to say that neither work as omnitanks. Their bulk is not that great to be able to survive multiple hits of the high invested AR ranged threats, and their healing is almost nonexistant. They are great counterpicks to deal with 1-2 or even 3 enemies, but they will not be able to “single handle” full defenses like BHector or Gustav can or how BIke used to.
This is the reason why I don’t think smokes are good on any of them, as they tend to pick their own battles instead of going deep into enemy territory (were smokes would have targets to activate against) and facetank everything.
When comparing both, assuming the same kit and level of investment, FLyon has slightly worse defenses (32/35 vs 35/40), way less attack attack (40+17 vs 41+23), same limited access to healing (specials and seals) and has no apparent way to prevent doubles. On paper, his DR would seem to be the key factor in making him way more tanky, but in reality, the extra attack allows Kiria to OHKO on retaliation many more opponents, avoiding 100% of the damage that a follow-up would do. In those situations (which are more common than not, as I my supports are centered on increasing attack), FLyon’s 50% DR becomes a glorified follow-up negation.
This is the approach I was having in mind when I said YLyon could outperform FLyon. He has better defenses than Kiria (40/43 vs 35/40), similar attack (38+23) but unlike her, he is not vulnerable to debuffs (which makes OHKO slighlty more reliable) and in my case, it’s easily mergable (making his attack indeed better). Micaiah is the other unit I’ve been considering as her DR and damage effectiveness might allow her to perform in a similar way, if not better, but I’m not 100% sold on that yet.
In the instances were OHKO is not possible, FLyon will defenetely be the superior unit (as he negates the double, basically), but like I said before, omnitanking is not as reliable as it used to be, so I made OHKO in retaliation the focus of my AR supports.
Side note: Can FLyon be better at OHKO in retaliation?
I’ve been toying with the idea to make FLyon more lethal, which revolves around Time Pulse (like you suggest too) and a more offensive special (like Ruptured Sky), but I haven’t found a strategy that makes it work (Pent might change that). Inantry Pulse on a team member would be a good alternative too, but unlike Pent, it only works on the first turn.
As for the Near Save tank. I would rather invest in someone who can reliably OHKO rather than in someone who relies on doubles to do so. For that reason I would pick Arden over BEphraim (dragons are not that common on AR-O, and even then, he has an effective 112 res), but I would wait for the upcomming BK and Zelgius refine before commiting. Is might be generous and give us something like a slaying effect, DR or healing.
If you decide to go with him, I’m not so sure the WF is all that needed. Like @MiThiKaL, he shouldn’t care that much about being doubled when he can unleash Ignis on the enemy. SF isn’t the best either (because he already has guard on his wepon), so maybe VF?
Conclusions: OHKO vs Speed tanking
As I final thought, I want to talk about how tanking has been evolving with or without the saves, because from your build suggestions I see a trend that might be misguided due to Brunnya status as an omnitank. I’m talking about debuff nullification.
Don’t get me wrong, debuff nullification is great and it’s always nice to have as an added bonus, but from my experience it is not a key factor on the survivability of a tank. The biggest issues are specials and doubles.
AR-D is heavily focused on being offensive. Their objective is to kill stuff and for that, they tend to overinvest in attack, speed or both (not to mention the prevalence of units that can force doubles like Bram, DuoLif or Thrasir).
Since tanks can’t reliable hit the same insane numbers (because they need to invest in three/four stats instead of two), that leaves them with three options: negating follow-ups through skills like Wary Fighter, forcing the speed check with a speedy NFU tank or avoiding the second hit through OHKO in retaliation. Since the introduction of NFU (and units with NFU prfs), the first option has become less and less viable.
We have talked a about how OHKO in retaliation is key for slow tanks like Kiria and FLyon. But even though I’m well invested on the OHKO strategy, I believe that the speed based tanking is the most reliable and future proof of the two.
This is the approcah that Brunnya fits in. It’s not her debuff inmunity that makes her great, but the extra stats she gets along the way, specially the speed. That boost plus her allies support allows her middleling speed to be high enough to avoid many doubles and even double some units back.
If you were willing to invest on speedy tanks (and you already mentioned Norne, who is in a similar position as Brunnya), then BEphraim makes a lot more sense.