General Discussion7.01 Invoker Discussion

With the massive changes that came to Invoker with 7.0 I naturally experimented around, did a lot of theorycrafting and watched high level players around my all time favourite hero, Invoker.
With that I have some questions or rather discussion worthy topics.

Shortly about me, I have about 1.2k games on Invoker on around 3.5k MMR, I watch a lot of pro games, so while I am ingame tactically as well as mechanically nothing special I do consider myself having an ok-ish understanding of the general game and a rather deep understanding of Invoker.

1. Skill-build:
The first thing that came to mind with the changes is, that (besides the obvious general nerf, not getting stats from qwe) it is quite a buff to quas. The regeneration is a lot more (especially with 7.01) with lvl 2 beeing the same as the old 3 and the lvl 3 now the same as old lvl 5. Also you don't need the fourth point in quas for double forge-spirits.
Still I see most players (and dotabuff trends) going for a 4-0-4 or 4-1-4 build. Why is it still popular to get a fourth point in quas. Forgespirit get 10 extra seconds, which is imo not that important from 40 -> 50 as for lvl 3, 30-40. Duration beeing over 30s seems for me the most important point. For coldsnap lvl3->4 is also a minor improvement compared to previous levels. Other spells also benefit also only in terms of a little bit of better slow.
I now saw some players going even further, leveling quas to 5 or 6 before leveling wex beyond 1/2 but I haven't had the time to experiment with that.

My go-to build the last few days was 1-1-3 and then going heavily dependant on the game. More Quas, if more control is needed, more Exort if more dmg is needed, more Wex if I constantly go low on mana and also for better mobility. This leads me in a game where my team is doing good to a more WE build, providing lots of dmg, both rightclick from maxed alacrity and obviously from spells.
In an even game this leads to a rather balanced QWE-Invoker, which is for me the most fun as I can make the best use of all spells and benefit most of the 6/2s invoke cd. In a game where we get behind this leads to a rather classic QW build (only with the earlier 3 levels in exort) providing good defensive possibilities with long range, long lift tornados, strong slows from icewall and good escape from highlevel ghostwalk.

2. Talents:
The level 10 talent seems pretty simple, depending on the game, survivabilty or dmg.
Level 15 is the obvious controversial talent.
My take on that: With the constant cooldown of invoke and the removal of double forgespirits on lvl 8/9 icefrog wants to make invoker focus more on fighting rather than on splitpush-power with double fs and bots. Also how much does the second fs give on lvl 15. I didn't do any math on this but it seems to me rather insignificant. 25% more XP is quite a lot and from the base concept of Invoker, a spell caster that realy scales far into the lategame the xp seem the better choice for me. With midas and this talents you can reach lvl 25 faster than mmost other heroes and that I think plays right into his favour.
Level 20 again is not that interesting, both rather minor upgrades I generally prefer the stats as it gives more of everything rather the little bit of dmg from the +as.
Then level 25: aoe blast or -15s cd tornado.
The AoE blast has good upsides in the right situation: versus multiple spread out right-clickers, defensively (no need to turn to cast it) and lastly looks pretty awesome. But I think it is very situational, only against the mentioned multiple rightclickers for the disarm. For a big wombo-combo I don't think it is that much better as you want for those kind of situations the enemy to be rather clumped up anyway to have the biggest effect for other spells. On the other side, -15s tornado. This brings tornado to a 15s cd, with Octarine Core (which you kinda want to have on lvl 25) you are down to 11.somethin seconds of tornado and with 2.9s cyclone duration you can keep enemys in the air for almost a third of the time. Of course the other spells don't get that reduction, so you can't throw 5-spell combos every 10s, but this is a rather rare case anyway. What can be used very effectifly is a mass of 2/3 spell combos, almost without downtime making you imo the most active teamfighter for fights that last longer than like 10s, which is most often the case in those lategame scenarios. You can go tornado-icewall-emp, go back out and in for ca 4s, tornado-meteor-blast, go out - in, tornado-strike-coldsnap and then you can in most cases start again with the tornado+first used spells. In those kind of lategame situations in a drawn out long fight where Invoker just runs around and casts non-stop were often referred to "Invoker dancing around" and with the -15s tornado I think those most enjoyable moments for invoker (playing or watching) are even more encouraged.
So to formulate it as question, why do most invoker skill the aoe blast over the cdr of tornado?

3. Items
With the nerf to his stats (via the levels in qwe) what are go to itembuilds now on Invoker?

As I stated I don't like investing into forgespirits thats why I think the Aquila route is by far not as good as it used to be, as it mostly was for giving better pushing and survivability for the forgespirits.
This leads me to an obvious starting build with Null + Tangos or Null + shared tangos + Faerie Fires.

Then into brown-boots + midas (eventually with some regen, most likely a salve and 1-2 clarities).
Then in my opinion on mana-item is needed so you can make use of the 6s cd on invoke and throw those spells out.
Euls is probably still a good option, but I also experimented with quite happy results going soulring as he gives you enough mana for most spells and the hp are not that hurtfull with the strong regen from quas. I also saw build going manaboots, but I yet have to experiment with that. For boots I like to now go phaseboots again as inventory space is not a concern anymore and the focus for me shifted away from splitpushing. (When I try manaboots I'll probably skip those though and go into travels without upgrading boots until that)
After that Aghs is still a must have and then straight Octarine, making you a spellbased teamfight-beast through all phases of the game.
Obviously there are many situational items before and after that (sticks, force, blink, linkens...) but as a general theme I think this build suits the allrounder-invoker best. I would be happy to get some discussion around invokers itembuild going as there are most likely other cool builds that are usefull. (For example I tried around with a quite fun safelane, WE, Atos, glascannon build or I saw a rightclick build mjolnir and what not, going for mass AS with alacrity)

Overall I'd like to hear the opinions on the new Invoker as I don't think he is dead with those changes but rather has a shifted focus, that is imo much more fun than the playstyle in the previous version.