Nano-ships are ships setup to achieve crazy-ass speed (that's a real technical term, half between "damn fast" and "ludicrous speed" on the Eve ship designer's scale) using Overdrive Injectors, Nanofibers, Inertial Stabilizers, Polycarbon Engine Housing rigs, Snake implants, and sometimes even gang mates with leadership bonuses. And of course, the Microwarp Drive.
The nano setup works better on some ships than others but its a common setup and the source of extreme frustration for a lot of players. Due to game mechanics a nano ship is often nearly invulnerable to capture and most damage is negated by the extreme speed, and while their DPS is gimped in order to go so fast a gang of nano-ships can be quite deadly and nearly invincible.
I used to be in the "nerf nanoships" camp but nowadays I'm on the fence on the issue since I'm more experienced and can see several strategies to deal with them at least some of the time but still feel they are very powerful even without some of the more expensive options.
So I think CCP will probably do something to nerf nanoships. In my opinion, they need only to address one module to fix this problem: the Micro warp drive.
The Microwarp drive gives at least a 500% boost to max velocity (550% for tech II, more for faction and deadspace versions) with a penalty to total capacitor and ship's signature when active. But despite these severe penalities, the benefit is such that many combat pilots insist that the MWD is a mandatory module on any PvP setup and not just for nanoships.
The MWD essentially takes all the velocity improvements of other modules, rigs, implant, and gang bonuses and enhances them such that a ship with a base speed of 242 m/s (the Vagabond) can reach speeds of almost 6000 m/s with just Tech II modules and Tech I rigs. Even ships not built for speed like the Ishtar can get up to almost 4000 m/s without trying. Smaller ships like Interceptors easily get faster than that.
The problem is not the speed though, its that all the weapon systems in the game seemed to have been designed with speeds less than a few km/sec in mind. And the only way to slow someone down, Statis Webifiers, have very short range and many ships simply can coast out of range of them due to the extreme speed they start at. (Minmatar Recons and Electronic Attack Ship having longer range webbers so are a rare exception.)
So in order to address this game mechanic that is quickly becoming too prevalent and unbalancing, I have a list of proposals listed from most drastic to least.
1) Remove MWDs alltogether and replace them with afterburners which give a more modest 100-150% increase in max velocity with no penalities and less cap usage. That way even the fastest ships possible will be only around 3-4 km/sec (and most less than that) and speed tanking will give some defense but not the invulnerability it gives now.
2) Reduce MWDs effectiveness by half or so. The end result is that some ships will still be fast but not as fast as they are now.
3) Keep MWDs as they are now but do not allow ships to turn when active. This forces ships to slow down to maneuvure making them vulnerable to enemy fire in order to engage. This is pretty drasitic however and makes the module have limited uses.
4) Increase the penalities (either fitting or operational) and give bonuses to ships that are supposed to be speed tankers in order to overcome them. Cuts down on the number of nanoships but not their effectiveness. And you know the powergamer players will go for those bonused ships anyways.
5) Reduce the ability of the MWD to enhance the speed modules, rigs, implants, and gang effects. It might drop a few km/sec off the top speeds and bring them into the realm of tough but beatable in a normal fight.
6) Reduce the effect of or remove Snake Implants from the game. These implants are often cited as the ones that allow speed tanking to go from difficult to deal with to nearly impossible. A few pilots are going to be outraged but the overall effect will be minimal.
7) Do nothing to MWDs, but introduce more offensive weapons to attack fast ships like area of effect webbers, longer ranged webbers, or more area effect weapons that can be used in high/low sec. Improving Tech II percision missiles would help for example, or making light drones faster. Stuff like that.
8) Do nothing at all.
There you have it. My partially informed opinion. Carry on.