So we should be mix of mobility, firepower and durability (this was mostly about our tanks and Battlesuits). But the design notes might have changed for us in the meanwhile.
If rules stay the same, we won't have firepower or mobility. We will just have durability for cheap :/
Our index was the most screwed up in terms of both fluff and crunch. That is why we expect such a big change (one that we will probably never get and many people will be disappointed because the tau won't feel tau).
I don't really want to go back to the riptide wing way of things. I just want something that I can have fun with. Weapons and units that are just numbers are not fun.
One of my favorite weapons in 7e was a comissar melee weapon that gave you counterattacks during fight phase. It was never really useful, but just trying to figure out how to make it work made me have fun with the game. And the fact that the rules looked so cool made me pick it quite a few times in my tau/astra soup army.
Well if our stuff get cheaper on the field we get more firepower. Mobility is currently nonexistent in our Index, yes. I think, since GW want to sell more models, we will get cheaper (so if you finally had that 2000pts build, now you will have to buy 3 more Crisis suits to get back to that value, mwahahaha!) which yes, will make many of us not be able to afford. But past has showed me that every time price of playing a standard 1850 army has gone up (price hike of a model or units getting cheaper points wise) there were complaints and later it calmed down, usually thanks to bundles or things like Start Collecting which to us is something like "Buy these 3 Crisis suits 5€ more expensive and get this Ethereal and 10 Fire Warriors for free." But I believe I am offtopicing.
I see what you mean with the Comissar weapon. Truth is I haven't seen much of the other codicii, maybe a bit of Space Marines, Chaos Space Marines, bit of AdMech and Astra Militarum. Most of what I have seen felt... uninspired. All of the units felt like "This is the role of this unit and this is the simple way it does it." while for example 6th edition Daemons of Chaos codex felt very fluffy, fun to play (but nowhere near competitive tier) and filled to the brim with fantastic stuff with weird mechanics and randomness which immediately made you think "how am I going to make this work and make it into at least semi-coherent army which can do stuff I want it to do?"
All of the 8th edition feels very very streamlined. Much less randomness and rules you need to remember but much less what you describe- stuff that make you think "This looks fun. I wonder how can I make it work." I personally don't mind that much since most of what I do is model and paint (Let's say 3-4 long evening in a week, 4-5 hours each compared to 2-3 games a month about 3-4 hours each) and they can't take fun out of it if I decide on a crazy color scheme or interesting conversion. But we will need to get into terms with fact that 8th is bleak and simplified (on the other hand 7th was maybe too full of special rules and untested rules and formations turning out to be OP or extra weak) compared to the previous editions. I have come to terms with it, but that doesn't means I wouldn't enjoy some weirder and more unique stuff for each fraction.
But back to the game of prediction. I want to see more people to write what they think will be in the new codex.
Walk softly. And carry a big BRUSH.