I will just be brainstorming a little here about some ideas that can possibly be included in an expansion for the game. To have at least some context in this article, I will categorize the idease in 3 sections
I don't think that anything of the following "ideas" need any explanation.
like a necromancer, an evil and a good priest, an Illusionist, etc.
preferrably with abilities in accordance with the new terrain or map new map-setups.
new terrain tiles
for example: Fixed, unmoveable portals or lava fields, waterfalls & rivers, etc.
more scenarios over two or more isles or empty squares within one island along with one or two that generate part of the map randomly (from a fixed pool of tiles or something) would be nice.
markers for a third and fourth player
this could easily be done with a set of green and yellow markers. Another tracking board would also be nice in this case. Along with this there would need to be scenarios for 3 and 4 players, of course. I would like to see team scenarios as well as free for all scenarios in this case.
Not neccessarily completely new, but more like special for the relevant terrain tile. Like "Skyforge City", instead of a generic city along with one or two extra rules or abilities. For example A unique Elven Forest could provide auto-shield for Elf units at the end of turn or to do a range attack against one attacking unit once per turn representing an ambush. Maybe even something as simple as a special land, simply providing 1 point more mana or defense then usual.
experience system from the computer game
Again something that would be new to the boardgame. The rules are already known, it is tested and could simply be done with a punch-out card-board sheet or two.
I think herein lies a lot of custimization potential for Guardians of Graxia. We currently use very simple rules: You may use everything thats's in 1 box, minimum 20 cards per deck to avoid a power creep. (Thus as not to load only Those units your guardians has affinity with) I think limitingcard selection to what come in one box, or providing additional cards to reach the maximum allowed with one base set and the expansion, is important, because otherwise people would feel frustrated to buy the base set again, just for the sake of one card or two. Also though our rules work pretty fine for us I would like to see something officially that was also playtested by more then just our group.
The going nuts
By far the most interesting for an expansion, after the second starterbox (see "expanding on the though of a 3rd and 4th player" below) for me would be a campaign. Espceially with the portals and floating isles a waypoint based campaign should work extremely well. I will refrain myself from going into details (tech-tree, campaign specific scenarios, creating new portals, floating (movin) islands, army movement, etc.), but I see a lot of potential here due to the unique setting.
Some new and unusual scenarios would be nice. For example non-player units that attack or ally with players under special circumstances. Maybe a morphing map or similar things. (Terrain altering Spells come to mind, too) Or some very special combination of victory conditions. For example: Player A gets points for holding fortified positions on the board and Player B gets points for reaching a certain destination. Both players could, in theory, ignore each other to fullfill their victory conditions. The catch is: The scenario grants each player the same amount of maximum vicotry points after X rounds. Thus the players have to try and prevent the other from achieving their goal. Also a multi-island scenario (3 or more) would be nice. That kind of stuff.
What I would like to see in the expansion is some more information about the background on the world of Graxia besides the standard blurr that is out there. Like: what exactly are guardians, where do they come from, how do you become one, what do normal people think of them, maybe even descriptions of some kingdoms or cultures of the world of Ggraxia.
expanding on the though of a 3rd and 4th player, new terrain, units and guardians
How about creating a second base set with completely new stuff for two other player colors. This way there would be two completely playable base sets, with different content. I recon that this might take a while to develop 240 completely new cards, but I think this still could be a very viable approach to include an option for a 3rd and 4th player into the game without invalidating anything that's already out for the game. For example there could be lava field and rivers along with fireelementals that can easily cross the lava fields and amphibians that can swim accross the rivers along with their respective guardians. I recon that by not reprinting forests, villiges and plains tiles the maps would be very ... unique, but add in terrain like an "elemental focus", caves instead of cities and maybe something like "a holy forest" and a stonehengy "earth columns" field and you can get a pretty nice box themend around the cassical elements. Add in some D&D like celestials and demons/devils and you get a pretty themey box with 6 races. I think this could work quite well not only expanding the range of races and terrain, but also the number of players at the same time.
My personal (and quite insicnificant and humble) wish would it be to see two expansion boxes: One bein a second base set with different player colors and all new terrain and cards, like described in my last point under "The goung nuts", and another one as a real expansion, with markers for all 4 player colors and all new stuff, like a campaign mode, more advanced scenarios and the experience system from the PC-game along with some more background story, rules for deckbuilding and an updated and more polished rulebook. (Pretty much in that order of importance)
So here are my 2 cents, and they got way longer than I anticipated. Please let me know what you think.