My plan is to do things a little differently this time as far as my main party build on my first playthrough. I say "main" because I like to mix and match my party occasionally based on the situation.
My first DA:O character was a human warrior and my main party was all human.
My first DA 2 character was a human(obviously) mage and my main party was again all human except for Varric.
So this time I've decided that my first playthrough will be a rogue elf. Also, my main party isn't going to include any humans.
Therefore, my main party will look like this:
Sera
Solas
Iron Bull
I had decided that Solas was going to be my mage after all of the mage characters had been revealed. Then I chose Sera because I wanted an archer and Varric was in my main party in the last game.
It took a while to decide between Blackwall and Ironbull but then I realized it could be interesting to have no humans this time around.
But here's the beauty of multiple playthroughs. I can have multiple main parties!
For my next three characters its looking like:
Cole, one of the mages, and whoever(probably Iron Bull) with my 2h warrior
Varric, Cassandra, and Dorian with my mage
Blackwall, Sera, Vivienne with my S&S warrior
My mage and S&S Warrior characters will actually be the DA:I version of my Warden(S&S) and my Hawke(Mage). I also wanted their party to be similar.
DA:O S&S Warrior: Alistair, Leliana, and Morrigan to DA:I Blackwall, Sera, Vivienne
DA2 Mage: Anders, Varric, and Aveline to DA:I Dorian, Varric, and Cassandra
So not only will I occasionally mix and match my party based on the situation in order to get a feel for all the characters, I'll also have different combinations for later playthroughs for an even more varied experience. Then knowing these new characters will inspire me to do even more playthroughs!