4 is fine (one for each corner), because these are for basic HV, not end-all vehicles. If they do allow more, there should be a diminishing returns that plummet from 5... making people just waste resources and weight adding more with no return on investment. --- My overall feedback on these is: Great! Everything about them, and their settings, and power/speed/restrictions is on par with their goal. They are perfect for a simpler structure to 'get you moving'. Also I love these 1x1x1 single units for attaching to 'utility hv'. Things like mobile fridge units, cargo pallets, movable work lights, and other such. Since all it takes is one to move, reduces 4 thrusts and an rcs (which bulk up and make a ruckus of noise).
Or no limit at all; it's not like these devices are terribly powerful (one directional thruster puts out 8x the thrust for only 2.5x the input power, for example). If someone really wants to float a 1 kt assault HV on 250 hover thrusters, I say let them waste the resources on it.
Balancing ... same for me if no limit. Can always turn off the "max amount" when start a new SP of course. In MP you probably can fiddle with a YAML or setting file - too. But IF to have a limit: With only 4 then a OK starter HV (lvl5 with most devices and some weaponry, but else simple) becomes sluggish. If put 6 or 8 on, in creative, then it handles OK. So instead of 2-4 more of the cheap starter ones, then need to put on the "normal" hovers, at least 4 thrusters and a RCS. With the expense of more fuel use and size and resources.
I realize the max for hover thrusters is 4, but I had to ask myself why? Is there something about the hover thruster that might actually make it better than the traditional combination of hover engine, thrusters and RCS? So I did a little math beyond the limit of 4. 8 Hover thrusters = 5 kN * 8 = 40 kN horizontal force front, back and sides. 1 Thruster S = 40 kN force thrust in 1 direction To have thrust in all four directions on the horizontal plane, you would need 4 thrusters, one in each direction. So 4 Thruster S could give you the equivalent horizontal force front, back and sides as eight hover thrusters. 8 Hover thrusters = 40 kW 4 Thruster S = 48 kW So the 8 hover thrusters and the 4 Thruster S would both be capable of 40 kN in the four directions, but the 4 Thruster S would cost 8 kilowatts more in power consumption. However, the hover thrusters not only save power, they come with some of the lift of hover engines and torque of a RCS included. My thought is that if the hover thruster just used a fraction more energy, you could probably drop the hard limit--unless it is a band aid for bugs in the game. 4 Thruster S + 1 (1x1) hover engine + 1 RCS = 54 kW. This combination would require fewer devices and weigh less than 8 hover thrusters. Also, the output of a single RCS and one 1x1 hover engine is vastly superior. So if this is so superior, why do we need a limit of 4 hover thrusters? My thought is that it has to be that large power savings of 14 kW. Now if the hover thruster used 7 kW each, then 8 hover thrusters would use 56 kW. At this point, the energy advantage of the hover thruster is gone too, meaning that it would have a great role as an early device as well as an all-in-one thruster, but the need to hard cap it at 4 for balance might be gone at that point.
