We will work on the assumption that there will only be one more raid tier here, as that is what we are expecting to happen. I am also going to try to keep this from turning into a wish list sort of thing at first. I will post what I think we will see and then I will get into the pipe dreams of what I would love to see, as in wishful thinking.
I am going to basically try to predict the direction they will take with garrisons first.
Level 4 Garrison:
We will be allowed to level our garrison to level four. It will not get any bigger, just allow us to build bigger and it will also open one additional small slot for us to play with that is already sitting there unused, as many have noticed. With upgrading to a level four garrison, which I can see costing around 5000 garrison resources and 5000 gold, we will be able to upgrade our buildings to level 4.
Unlike the level 3 patterns that needed an achievement to unlock them the level 4 patterns will be attainable from the blueprint vendor next to your architect table in your garrison as soon as you upgrade to level 4. The cost would be 1500 gold for the blueprints of all level 4 buildings. You will also be able to get two new books intended to be traded in for two level 4 blueprints from doing the quests in tanaan jungle and they will be traded in at the same place you traded the other books in.
Each level 4 building will add new bonuses to them, of course, and level 4 profession building (if you do not have the profession) will allow you to craft new starter gear close to that current raids item level that will be upgraded just like the previous ones. People who have the profession will be able to buy the patterns just as they purchased the previous patterns.
The new small slot will be capable of holding any small building you wish. You can go with another crafting station or you can go with a storehouse or salvage yard if you did not already have one. The choice is up to you.
Each new building will come along with new quests, such as opening another portal in the mage tower, getting a new mount quest line in the stables, etc.
There will also be a legendary follower that comes along with the achievement for upgrading all buildings, including the standard ones like mine, fishing shack, pet menagerie, and garden, to level 4. A second legendary follower will be awarded with the completion of the legendary ring quest line.
This is what I can see happening in the future with garrisons, at least what I believe we can reasonably expect to see. Nothing I mentioned is crazy to expect or really out of line with how blizzard has done stuff in the past. So I would say it is all possible. Except maybe the legendary follower for upgrading all buildings to level 4, but I can see the legendary follower for finishing the legendary line. It would be one of the familiars.
Now, for what I would want to happen, but I know won't happen.
I would like all crafting materials made in the buildings you have to become BoA and not soulbound. So I can have multiple engineering buildings sending all their gear springs to my engineer. Multiple tailoring buildings sending their hexweave to my tailor, etc. I would really love to see this happen, but I honestly do not expect blizzard to be this generous to us.
It would be too over powered for people with many alts and might make others feel as if they "have to" level alts to run buildings, and we know that after last expansions "mandatory" heaven that blizzard is making every attempt they can to shy away from anything too easily labeled mandatory. Doesn't change the fact that I would love to see that happen.
I would also like to see the ability to change slot size. If I wanted three large buildings and only two small ones that would be one hell of an option to have. Once again, I do not see blizzard doing anything like that, but it sure would be cool. Not because blizzard would not want to, but because the size of the plots are kind of written in stone there and as such there really isn't much play room that could allow us to switch sizes.
What would you like to see in the garrison of our future, both reasonable, and wishful thinking?