Linde refinement

It's just a way for Intelligent Systems to get people to think a bit harder about who to put on a team. Team composition has been, for the most part, fairly simple. While the units on the team can vary, what's in the team (as far as weapons) is fairly similar, unless you're using something like Dragon/Armor Emblem.

(This is me assuming that you have a neutral Linde)
"At start of turn, grants Atk+6 to adjacent magic and staff allies for 1 turn. If unit is within 2 spaces of a magic or staff ally, grants Atk/Spd+5 during combat"

If you're going with her new Aura refinement, then I'd suggest putting a more 'tanky' mage on the same team. While her speed is amazing, especially with her refinement's +5 'in combat' buff, both of her defenses aren't that great, so I'd suggest going for someone like Deirdre, Julius (if you don't care about merges), Soren (with his Owl-refinement) or some healer with high resistance (like Wrys, and no I'm not joking, lol). Soren, I would think, would be pretty good for this since his refined Wind's Brand allows him to have +6 to his stats when near all of his allies (or just +2 if next to Linde), or Julius since his resistance is absurd, and his damage-reduction-potential is even more outrageous.

You could also go for a tanky healer, like the Absord+ Close Counter healers, or even Canas (he's really not as bad as people are making him out to be, at least stat wise).

Having a team of magic users isn't really too rare (Dragon Emblem, although they're more of a special case), so while it's not the best since you don't have any physical-attacking units, it's not absolutely awful if you have someone like a Bladetome user on your team (and maybe someone with Windsweep for those annoying Distant Counter units? lol).

Then again, you could just put in two physical units, like Lukas, to tank physical hits for Linde, and anyone else that needs protection.

I refined Linde's Aura when it came out - here's my current build with +HP/-DEF IV's. I like running her with infantry Blade tome users like Nino or Tharja since she provides the visible Atk buff as well as invisible Drive buffs. Not to mention that the extra Atk/Spd buff for being near mages is a really helpful buff for her. Overall I like the refinement because it gives her utility as well as improving her own combat.

Team comp: I usually only ever run her and one other mage, but I might run her with a staff user in Tempest Trials (since staff users also benefit from +Atk to provide more healing.) Dark Aura is easier to craft teams around, but it also doesn't provide buffs to Linde herself so it's a good trade-off.

I also don't use Linde in Arena since her BST is too low, but she's useful in Arena Assault and can nuke armors either with one shot, or doubles if you can manage to get her into Desperation range. I also plan on using her in this TT since she can get into Desperation range and basically stay there and sweep for the rest of the maps. For example, my upcoming TT team is Karla, Linde, P!Inigo, and Dorcas.

Hope that helps, but if you have any other questions, let me know!

Don't know if it will help, but I'm planning to put her on my (Work in progress) Owlteam. I have Soren +2 who is already bulit up, Robin +10 with Owl and a yet unknown red owl mage. She'll fit there well with her bond skill and attack buff as well as being a decent ally for everybody by finishing weakened enemies or getting safe kills herself.

The aura refinement works really well in CC or TT, since taking a healer there is a big plus.
Giving +6 atk to mages and healers is a nice boost too, and getting+5/+5 to atk and spd in drive range is insane.
For arena purposes i guess its not that good, but i do like it in assault too, were i don't have to worry about scoring.
All in all i have been enjoying it quite a lot.

I suggest you watch some YouTube videos of Lu Bu Feng Xian healer emblem. It really encouraged me to think outside the box, forget just briefly about colour advantage or what units are "supposed to" or "designed" to do and just look at the numbers and potential.

That said, I've been meaning to look at team-building possibilities for this refine so let me see...
Linde
Aura +eff
Draw back or swap
Glimmer
Swift sparrow, probably
Desperation
Hone spd
Fortify def

Nino
Gronnblade
Draw back
Glimmer
Fury or swift sparrow
Desperation
Spur def
Spur res

Sophia (W.Tharja or Henry could do similarly; W.Tharja and a mounted healer would make a tactics team possible) -HP +def
Rauthrraven or Rauthrowl+def (or +res)
Reposition
Bonfire/iceberg
Close counter
Quick riposte (or guard and QR seal)
Hone spd
Fortify res

Azama -atk +spd (or +def or +res). alt: Lissa, Sakura, or if you want cavalry, Nanna, who might not need guard.
Dazzling pain+
Martyr+
Fortress res
Guard
Savage blow
Savage blow

Linde and Nino blast stuff to bits, and Sophia will run in to take them out of harm's way. If the opponents have too much res, chip them down with pain+.

If you want to get fancy, swap out Nino for flying Nino or B.Sanaki and use guidance; could also mix it up with H.Nowi and +def CC H.Henry using a W.Tharja setup (but then you may as well just use W.Tharja).