I’m going to answer the title first, then I’ll talk about the Fire Emblem question a little.
“Does society prefer defensive or offensive strategy?”
In general, for most competitive games, the environments around them prefer an offensive strategy.
Overtly defensive strategy is seen as cowardice or lame, while offensive strategies keep viewers entertained and engaged.
The irony of this is that in many 1v1 games hyper-defensive play is actually the best strategy. Usually one player must sacrifice something to initiate an attack, this leaves the defending player at an advantage. This is particularly notable in Competitive Singles Pokemon (Smogon, VGC found a way to fix this) and Competitive Smash Brothers (Not sure about Smash 64, I think the conversions you get off of a hit make that game more aggressive).
In entertainment media, there is a bit of a trope of the old, wise, and experienced guy waiting for the younger guy to strike first so he can effectively counter-attack. This is generally true in games where both sides can see the board/arena equally. (A lot of the fencing type moves high level players will do in fighting games are to bait out a bad attack from their enemy so they can punish.)
This changes once each side cannot see the whole board. If you cannot see the opponent they can make an attack under the cover of dark and regain the advantage by attacking a place where you may not have the most solid defense. This is what makes Mobas and Shooters work so well at a competitive level: offensive play will always be good.
These are a lot of general statements, so not 100% accurate, but this is generally how I see pvp games until you add team elements.
““high landing and high damage to both sides for a proper turn based strategy””
I think this mindset is foolish.
Fire Emblem as a series already has an issue with a lack of unit teamwork & the closed exp system encouraging a few units to get buff while the rest die or get benched. If you play with unlimited exp (FE8 and Modern FE) then this is removed and teamwork between units is encouraged more.
In the old exp system (which is still popular & what I’m more familiar with) this mindset increases the divide between “units who can” and “units who can’t.” Rescues become mostly unnecessary, chip damage becomes mostly pointless, and the player can stand outside enemy range while healing up with vulneraries. A lot of this has to do with map design and enemy AI, so of course I’m speaking in general terms. I think the greatest loss though with this system is the “in-between.” If each confrontation with the enemy is completed in 1 round then you lose those messy inbetween turns where you scramble around your team, reposition, reform walls, rescue, heal, transfer items, ect, all while enemies are right next to you and about to attack. This was one of the big things which attracted me to fire emblem as a series: those messy, chaotic turns where everything’s going haywire while you hold your team together. Naturally you experience less of that as you get better at the series, but removing it entirely is a great loss to me.
My next point is something I think most anime viewers will understand: battles take time. Obviously this isn’t realistic, but for the sake of an anime-inspired fantasy jrpg it works brilliantly. The time a battle takes doesn’t matter much when your whole party is together fighting as a unit, but once there are external factors (The team is split up, there’s a time limit objective, one guy needs to get to a certain part of the map before the enemy does) the time a battle takes is significant. You might send an armor knight one way to pull a group of enemies and buy 2-3 turns while the rest of your team runs by, (or runs away). You might want to kill a unit for the item drop he’s guarding but that would take you an extra few turns out of your path.
And finally, high damage output from both player and enemy lends itself towards puzzle-emblem. I appreciate the merit of sweeping an enemy formation in 1 round (Echoes did this a lot in the final dungeons and it was really fun), but more as a way to see how far your group has come and how much stronger they’ve become. It makes you feel awesome. But for a traditional FE map I’d rather not cut through all the enemies like butter -which was one of the things I hated about fe7.
Edit: after reading the other replies, I will say that my feedback mostly pertains to chapters less than 16 rounds in length. If you make a large seize map which goes on for some 20 or 30 turns then yes quick kills are good because they make turns take less time and reduce the amount of factors affecting the player at any given moment.