Hi, I'm new to the game. I have played the first game a bit but Endless Space 2 is all new to me. And i just fell in love with Vodyani aesthetics and their style of play and mechanics. But as i understand their Arks has been nerfed some time ago and I do not think that was a good idea and let me tell you why. As you know Vodyani do not colonize systems in traditional way that other fractions do, instead they build their Arks so their Arks IS their colony in a sense, and yes I understand as people complained that Ark is a powerfull ship in the beginning of the game that could be used offensively. But this is so really if you get really lucky in the earlygame, namely you will need atleast TItanium to rig a TItanium Slugs A2S on an Ark but if you do not have it on your Homesystem you'll need to find in somewhere else (you also can buy it on the market, but you need technology and dust to do that, but still there just might not be any Titanium available on the market so even if you have good FIDS and good flow of Essence you still cant utilize them without strategic resources), and playing against Vodyani you shouldnt sell Titanium on the market in early game. But then you'll need Ark to sit in other system and extract resources wich means you'll need another Ark to utilize this Titanium and all this requieres Essence source of wich you may find near or you just aswell might run futile first 5-15 turns. So what i'm trying to say that it's all luck based.

The second thing is that other fractions may build upgrades in their systems that makes assaults on them much tougher like, bunkers and use heros to further boost colonys defence. But the Vodyani only have Arks wich you do not need to siege to destroy, you do not need manpower, you do not need to upgrade you ground forces and other things, all you need is to make a strong enough fleet and Arks goes bang in mid or lategame. All Vodyani player can do is to assign hero to an Ark and make a defending fleet in the system. But when you have more than seven stationary Arks it is impossible to hold such fleets in every system, upgrade fleets so they remain effective wich all drains you resources and you'll have to pay immense upkeep also. Why you need a fleet in every sys you might ask? Well becouse with Baryonic Shielding fleets can move free, and attack might happen anywhere and your Ark goes down in a single turn. But i doubt that you might assault a conventional colony with 2 or 3 thousands manpower, with tanks and jets just as easily, so defending side has a bit of time to organize a defence to repel the attack. Of course you could unancher the Ark but what is the point, in you loose all you FIDSI, well you lose everything, and even if you park it somewhere else other player might just chase you down and Ark is destroyed again. You can't be some space nomad in mid or lategame. 

So i have been wandering about it and i think there is a several things that might be done. 

1. The first thing is that if the ark is anchored in system for 10 turns you have not only to battle it as a ship (when other player wins a fleet battle against an anchored ark it becomes Damaged and loses all it's combat capabilities and movement speed), but also you need to siege it like a planet. So Damaged Ark becomes incapacitated and vulnerable to other player to siege and destroy it. The Vodyani player might repair Ark with Essence and Dust. But if Ark is unanchored if it looses fleetbattle it goes down like any other ship. I think this would prevent players to risk their Arks.
2. Give an anchored for 10 turns Ark a special ability that makes it inpossible to attack it for 2-5 turns, (call it Shield of Virtuals or Essence Shield) to activate this shield you'll have to use a large amount of Essence and/or Dust. Unatchored Arks cant use such shield.

Also Vodyani can't really compete for early game quests like finding ten anomalys and other small tasks, becouse the only thing Vodyani player is concerned at early stage is finding a source of Essence. Therefore you are at a disadvantage with the first major or minor civilization that you find, becouse when you take Essence from them you cannot develop good relations with them, like the other Civs can, witch worsens manpower problem that Vodyani have, and they desperately need manpower to crew their ships and invade others. Also minor civs spawns pirates but in order to get Essence Vodyani have to sit in the system with their Leecher and defend it against the pirates, so you have to have very early military in order to not lose you only Lifeline - the Leecher, wich again wastes you turns building soon-to-be-obsolete-ships in time that you could have been building Public-Private Partnerships or Cerebral Reality or any other early game buildings. And the first Vodyani personal quest that spawns even more pirates on you head doesn't help either.

I understand that Vodyani mechanic and playstyle revolves around exploiting of others and expanding, but if you go against just as powerfull or more powerfull civs than you like Cravers or Unfallen you just cannot defend youreself, there just no way to do so.

So this is my thoughts on the game so far, it could be that i'm just a novice and do not understand everything properly, but I do not think Vodyani that strong really, those whos saying that they are strong just can't optimize their own strategies against them and they need to get good. Anyway, there it is. 

Oh by the way another thing.

When Vodyani takes out a system or crush a minor civ the system just goes in neutral state, when everyone could colonize it, and I suspect Lumeris can take anvantage of that and just put an outpost there right under Vodyani nose. I think that you sould not be allowed to colonize system until a fleet stays there and protects the system, or while Vodyani Hunting Ground is taking place. Can someone correct me on that?

P.S.  Sorry for my English, is is my second language. I'd post it in my native Russian section of forum but i do not know if you even read it.