I like to call the two uses of cloak described in the OP "strategic cloak" and "tactical cloak".
Strategic cloaking is cloaking to make your opponent unaware that units are present. It is the type of cloaking for sneaking around or through bases.
Tactical cloaking is when your opponent knows basically where your units are, but precisely count or target them since they are invisible.
People tend to like, or at least accept, strategic cloak. It's somewhat rare and can be cool when it happens, although at the time it sucks a bit to be on the receiving end. Tactical cloak is the domain of permanently cloaked frontlines. It is worth noting that these aren't strict categories as something like a cloaked Lance is unknown until it fires. This falls somewhat under strategic cloak as the cloak is making the unit unknown, rather than just making it hard to target.
Tactical cloak has been nerfed pretty steadily over the past few years, while strategic cloak has barely been touched. This was mainly done by increasing decloak time when firing, but I think decloak radius was also increased at some point. Mobile cloakers had a radius nerf quite a while ago. Cloak parameters work on this idea of innate cloakers and non-innate cloakers. Non-innate cloakers have a set decloak radius based on their size and long decloak delays. Innate cloakers have whatever decloak radius is appropriate for their balance, but when they are under an area cloaker they get the default decloak radius, if it is smaller, and don't drain any energy. This is to prevent anti-smart or anti-synergies with innate cloakers and area cloakers.
The decloak times are currently pretty high.
| || Proximity decloak time || Every other decloak time |
| Innate cloakers || 1.5s || 3s |
| Non-innate cloakers || 3s || 6s |
What this means is that a non-innate cloaker cannot cloak for six seconds if it fires a weapon while cloaked. I recall doubling this from 3s, and it was a pretty big nerf to Scalpel fighting under a cloaker. Previously Scalpel was cloaked for half the time while fighting normally. It made Scalpel vs Scalpel pretty silly given how homing works. The nerf also made it possible for an alert air player to snipe Lances after they fired within the 6 second window.
Tactical cloaking possibly needs another nerf. I don't want it to be useful though, and I'm aware that the point "not useless" will still see some people complaining about it. But anyway, a nerf probably requires some new tech. Here are the ways area cloaking can currently be adjusted.
The usual unit stats. Build cost, move speed, health etc...
Increased energy drain.
Increased decloak radius while area cloaking (these are not reduced by being under an area cloaker).
Increased decloak radius for non-innate cloak.
Increased decloak time for non-innate cloak.
It's worth thinking up new mechanics that could nerf cloak, and this thread has a bunch of ideas. In general I would like to avoid mechanics that are "too numbery" or anti-smart.
An anti-smart mechanic is one that gives units new "choices" (or perceived choices) and thus new ways to be less than smart. As dyth68 points out, paying energy for every cloaked unit could lead to situations where someone doesn't want a cloaker to pay to cloak their allies units. Being anti-smart can be fine, but it has to be balanced with player frustration at things that they feel their units are doing stupidly.
A "numbery" mechanic is one that only changes the numbers behind the 3D world the units exist within, while barely impacting the ways units interact and move around space. Such mechanics run the risk of being invisible to new players, and can cause experienced players to play the game in formula-land rather than spatial-land.
I like the idea of a cloak capacity, either soft or hard, but I'm not sure how to make it work. It can't work on unit count because then it just makes people cloak a single Dante rather than a bunch of Kinghts. A threshold based on metal cost or mass feels very numbery. Perhaps we could reuse the Light/Medium/Heavy transport categories, but then Blitz and Flea would be in the same category. So this approach seems tricky. I am also not sure about large energy costs as they would just push cloaking into the lategame.
It's worth noting that strategic cloak is broken as soon as any unit under a cloaker is revealed. The enemy knows that something is there, so the whole unit blob no longer has pure strategic cloak. So perhaps we could make a system that "penalises" cloakers whenever their inhabitants are decloaked. It seems hard to do this without either making it too hard to recover from a strategic decloak or designing something very numbery. Mobile cloakers are already made easier to find by their large decloak radius.
What exactly is the problem with tactical cloaking? Is it artillery poking away and disappearing when a response appears? People massing shorter ranged units to defeat attempted pushes? Cloaked Snitches? Cloaking Dante to close the distance with defenses? Just not being sure what your opponent has? And which source of area cloaking causes this? I least like the defensive aura style cloaking for fire-at-will artillery which just uses cloaking as a way to make the unit a bit harder to respond to. I'm fine with units that aren't strictly "in combat" being cloaked, and closing distance with cloaking seems like a nice active use of it.
I'm starting to think the best approach may be some relatively simple nerfs. The issue might not be any particular use, but more the fact that a single cloaker has enough range to fill multiple roles on a front. A single static cloaker behind a wall can simultaneously cloak some backline Lances, provide a safe place for short ranged units to mass, and even allow for some defensive Snitching. Mobile cloakers don't need that much range for their strategic cloaking use. Perhaps a good rule of thumb is that putting any significant number of units under a cloaker should make them weaker to area of effect damage. That is not true at the moment, as cloakers cover so much area that players need to barely change how they position their units to benefit from it. So what about something like the following.
Cut mobile cloaker range by a bit.
Make static cloaker directional (with some turn rate?). There would be a "point in a direction" command that could be targeted on allied units.
Static cloaker could go down to something like 70% radius, but still have the same reach via an offset cloaking sphere. This would make it about as useful as it is currently at covering Lances or defensive Snitches, but it couldn't do both at the same time.