1. Oghren. Hes cut back on the drink slightly to make himself a good role model to his son but hes still drunk and crude enough to be awesome. I love Oghren. Hes like that crazy, drunken, axe wielding uncle I never had.
2. Bethany/ Carver Hawke and/or Charade Amell. Provided they survive their respective playthroughs and that you do not take the Gem of Keroshek off of Charade it should be feasible to have one or both of them make an appearance making reference to Hawke.
3. Nathaniel Howe. Liked him in Awakenings would have liked to have seen more of him in DA2. Hopefully him Oghren, Sigrun and Velanna can all appear as a Warden Strike force in Inquisition.
4. Herren and Wade. Simply put I like custom built superweapons like Vigilance and Golem Shell Armor. More of these please! Also because Wade and Herrens dialogue in DAO and DAA was absolutely hilarious 'Ah my one glittering, shining moment, and now I am stuck here at Turnips Keep!'

5.Loghain. If he survives I would like to see how he is progressing within the ranks of the Grey Wardens. Hell maybe try and convince him to put his general capabilities to work as a General within the Inquisition.
I will not bother mentioning Hawke or the Warden. They are more than likely to make an appearance. I only hope that if the Warden does make an appearance they either keep his/her face covered and voice muffled or they let us choose what their face looks like. I suspect it wil be the former but I expect to be pleasently surprised.
As for Hawke since I always tend towards using the default looks. I have no problem if they use Hawkes default features for either gender.