No I was definitely talking about LoT1, when I mentioned using Sanae as an offtank. Maybe my definition of an offtank is broader than most people, I don't know.
I am kinda see what you are trying to say, if I understand correctly about your definition of "off-tank". You are saying that Sanae can be built to be a tank in both DEF (and MND) similar to Remilia but to a lesser extent if you deliberately give Sanae better gear, give her more Library point and focus on her DEF only.
I think Sakuya is good in both ways. Full offense Sakuya needs powerful buffs for her Killing Doll to actually do some good damage (might be a bit weaker than Spear the Gungnir) and she can also buffs her Speed to the max to spam it. Building her this way sacrifice a bit of her bulk.
While Speed buffer Sakuya needs to be switched in quite often to actually makes a huge difference with 80% speed buff on the entire party. Honestly, who doesn't want to get more turns than enemies? And building her that way lets her safely sit at 2nd slot most of the time in my playthrough.
Moving on to the LoT2 balancing. Well, there are quite a number of reasons for it to be less balanced.
Skill, Subclass and improved damage formula all make LoT2 easier but I think some of you might not also consider the following that make LoT2 easier than LoT1 or make LoT1 more fair than 2:
1. You can see enemies' HP bar. That negates your feeling of tense of a hard boss and just go bullrushing it with Gambler Nitori, Eiki, Flan...you name it.
2. Most Main-game bosses in LoT1 don't have either absolutely high DEF or absolutely high MND which limits your ways of attacking. When I attack Reisen with either Physical or Magical, I don't feel any differences even though Boss!Reisen is supposed to have high Mind. From LoT2 wiki's bestiary, most bosses are lopsided in defenses and I think the only boss with extremely high Defense and Mind are Tenshi and the final boss. (Well, in the main game at least. The postgame needs to be fixed, really.)
3. End game bosses in LoT1 have multiple phases so that they can't be defeated until their last form. (Rinnosuke, Maribel) while the sword in LoT2 can be killed even at its first phase.
Also, I think the only broken characters in LoT2 are Nitori and Flandre which was also true in LoT1 and they are absolutely broken if you purposefully give them WAY more Library point than they should have.
Speaking of which, someday I might try a team of the "worst" characters in LoT2. I want to see if they are really bad/overshadowed by others. The following are my thought (in terms of usefulness.) and not gonna cheesing some bosses with Iron Mountain Charge from Monk subclass.
Marisa
Youmu (Attacker)
Cirno (No synergy)
Nitori (NO Maintenance skill, period.)
Mystia (No synergy)
Utsuho (No synergy)
Eirin (No Healer subclass, might also no People of Moon skill)
Sanae (No synergy)
Remilia (No synergy)
That's it for the worst and the rest are just for the sake of having some buffer and debuffer. (every team needs them, you know.)
Keine, Aya and Reisen (No People of the Moon skill)
What do you guys think?