Keep the same engine. Just my opinion, but I rather have the same thing, with more content. Now that Heroes 5 is patched and exp'ed, general opinion seems to favor it as a whole. Why waste a year of labor on a new engine?
Two more factions. Double map objects. Heck, a third creature upgrade tree. Gaming has gotten to the point where H5's graphics are fine enough, do some tweaking, but please, don't 3 to 4 or 4 to 5 us were we get new graphics, new engine, and half the content. I want more stuff. Not new graphics. I'll go play a first person shooter for graphical thrills, but in this line of gaming, us hardcores want quality over cheap thrills! Also, (for us old hardcore fans), remember 1 to 2 to 3's progression? It was beautiful. Each time we got some better graphics... but two more factions! And loads of new objects, terrains, and the like. That's what we need. Base 6 should have ten factions, then two exp's for 12.
That'd be awesome.
Swamp team should return, that'd be good. A mix magic warrior type like the dwarfs, with gorgons and the like. Or just do Nagas... whatever.
Ice team would be a nice new addition as well. With yetis and boars and ice giants.
Really I don't care what teams they add, or what map objects. But I would love ten factions.
Increase performance on AI turns as well. Polish the game to a shiny glint. It'd be great.
I look forward to hearing your thoughts fellow gamers!
<Beyond Here is Updated>
Here are my thoughts on that ice town I talked about a second ago.
Name: Citadel: Basic Stats, Attack/Spell Power
Theme: An ice themed town, it's in-game image a spiraling mountain with smaller pillars ascending along it's side. The main races of the town are ogres and giants (two races we haven't yet seen in Ashan). The main castle sits on the peak of the main mountain. Think of Stronghold in the snow, with some haven mixed in, i.e stronghold ogres and haven giants.
Hero Type: Pathfinder. Race is Ogre. So we are looking at a more intelligent realization of the race. They've already basically said via unit type on Stronghold that ogres are not a barbarian people, nor do they live to the east with the other tribes there. Maybe I'm reading in a bit too much though.
General Exposition and Coloring: The main colors of the team are Teal, Brown, and Red.
Most non-upgrades I would imagine being garbed in brown furs, or natural hair of the same color. The upgrades, (depending if six has two sets) are either teal or red colored. One flavor being a type that lives on the outside of the mountains, exploring and taming the highlands, who's skin and clothing(?) would be blue and teal, while the other being a type of the creature that lives in the lava filled caves below the mountains' crust, and thus have a reddish color overall. Just for the "awesome effect", mind you.
Unit Tier 1: Boars, similar to those of Heroes 2.
Upgrade 1: Highland Boars who have snow covered coats, giving them the upgrades' set distinct blue coloring.
Upgrade 2: Crag Boars, who have black singed coats.
Reasoning for Tier: The Boars are truly a staple of Heroes 2, I mean, halfings and boars on the same team? You got me right there. They also fit in well with a highland/snow themed town, and mix it up a bit.
Nival has moved away it seems from animals being a part of the factions, save unicorns and other larger, more mythical creatures. The boars would be a sign of willingness to add the flavor back in that was missing from 5 in this regard.
Considering the "Pathfinder" being the faction's hero type, it wouldn't be so strange for a hero to have nothing but boars on initial recruitment. A ogre warrior running around with his pack of tamed mountain dwelling battle-hardened boars? Oh yeah, that's awesome.
Unit Tier 2: Cave Troll. The lanky spear throwing variety. Or could go with the H4 club wielders. Nah'... they always creeped me out...
Ranged unit. Has a limited throwing distance for his spear.
Upgrade 1: Ice Troll. A frozen warrior that excels at skirmish tactics. He has an extended range beyond his base type, but can't shoot across the whole battlefield. To balance this, he should receive a bleeding effect on his attacks that (*Poison*) enemies.
Upgrade 2: Crimson Troll. A caster troll with a weak attack, and both a slowing frost spell and a "damage over time" fire spell.
Reasoning for Tier: Trolls have never found a place in heroes, in a faction. Always loners these poor brutes just want a place to call home... *sniff*... just want to hold on to their mommies... finally at home... well, true, they were in H1's and H2's Barbarian factions, but that was a long time to be away from the baked cookies, apple pie, and images of old ladies knitting sweaters. They need all that back.
Unit Tier 3: Harpies. Much like H3's, they attack, but base Harpies have "No Retaliation" instead of attack and return.
Upgrade 1: Mountain Harpies. Attack and Return, and No Retaliation. Give dungeon something else other then the Furies. Like Wererats. Just kidding!
Upgrade 2: Grave Scouts. No Retaliation, and they get a special ability to fly over to a target within movement range, and make that target unable to move or retaliate against any other creatures. The ability stays in effect until the Grave Scout moves away or attacks another creature.
Sorry it took so long to get this little bit together... it has been a busy few weeks, and I'm now sick, which is pretty much why I was able to get back here. I'll throw up the next four creatures later, along with my ideas for factional spell benefits.
So far, I see this faction being an offensive "Haven" type, with well balanced unit types, including two shooters, two fliers, and three ground. And the ability of the use of spells.
Enjoy what is here to maul over, and thanks for reading. If this cold doesn't let up, maybe I'll update even sooner then I expect.
<--- You're the guy hanged if you ever dare to touch my blacksmith!
anyway, i don't think more is better but i think we should get like 1 or 2 new factions and maybe like mix the dwarfs with somthin else.. i dunno. dwarfs only have ONE non-dwarf unit which i think is bad. 
