GENERAL
the ADS had enough isk/sp barriers to actually warrant such a high bonuses. Apart from that the thing that really broke the game wasn't even the fact that it existed, the fact was that so much isk was currently in the game because of poor Planetary conquest decision (that were fixed waaaay too late) that many players could abuse the use of vehicles in general. Where the regular player could afford to lose one every 2 to 3 matches maybe more depending on the fit these people did not have that need and could simply spam them giving much grief to other players and creating a horrible game experience. Matchmaking was also a big factor (resolved) in which you could have 2 full squads in one team and no squads in the other, one abusing vehicles and the other team proverbially taking it like a pornstar.
POWER RATIOS
If it's power that many people where afraid or pissed off about, the should only need look to the fit of the month players who regularly get 20+ kills on a regular basis, a very conservative number since many passed the 30 and 40 mark, without having to use an ADS. SO power level was in fact balanced since at such a high isk/sp barrier your performance was akin to that of a mercenary on the ground.
GUNNERS
On the other hand, when talking about gunners, people could only say it's a bug but the evidence in the code changes demonstrate that skill stacking has always existed and there was even an active choice as to what skills stacked and which didn't. To this I bring the example of ammo capacity and proficiency. ammo capacity stacks and proficiency doesn't. I would like everyone to know that this paragraph isn't merely defending the status quo of maintaining what many forum warrior believed to be an unbalanced mechanic but the simple fact is that there where many barriers and balancing aspects to the whole pilot gunner dynamic that the regular joe simply did not want to fuss over.
For example I was a dedicated pilot and had a dedicated gunner with both of us maxed skills. We would kill tanks very easily because they were not specced or skillfult. when a skilled tank came one would ussually have trouble taking it out since they knew how to move and what to do. The same thing goes for infantry. A good infantryman could simply avoid spotc where the ship could attack and consequently avoid damage altogether. Forge gunners could simply deny everything on the map, since thy could hit you before you could hit or find them. Against ADS and vehicles in general I would use a breach forge and my buddy would use an assault foge and we would destroy vehicles in no time. It was al about the regular player not wanting to waste time and think about what they could do to actually make a difference. Run and gunn is the only mindset most have.
GUNNER/PILOT ENTRY BARRIERS
as many people know it takes about 2.4 million skillpoints to max out the racial ads skill. Not to mention the prerequisites of actually getting to this skill. Lets say a total of 3 million per character pilot and gunner to have this power level. Add about 5 extra million minimum for the pilot since they have to have the fitting skills maxed out to be able to actually be effective with his ship you have a total of about 11 million skill points base for a good ads gunner duo. Now, realistically a pilot gunner duo would have to spend 500k minimum on a dropship. Thats 250k per player (same as a proto suit) for similar advantages.
RESULTS
In my experience with the pilot/gunner combo the average kills per match were 30 for the gunner and usually none for the pilot since my focus was positioning and staying in the air. If you divide 30 kill by 2, remember its a two man team and one person cannot be attributed all the glory, the average kills per person in said dropship is 15 which is by far overpowered. Now for the sake of argument lets say they average 50 kills per match, that would still equate to 25 kills per player in the ads which is well withing the boundaries of top players using FoTM or their weapon of choice for the isk/sp ratio.
VERSUS VEHICLES
Versus vehicle both ships had their potential as solo boats and an exponential increase n damage with a gunner. This exponential increase though did not mean isnta wins. Intelligent vehicle users did know how to avoid damage and the less experienced or skill(sp) ones lost as is the case in most situations that involve sp/isk investment.
OTHER THOUGHTS
The ADS changes go too far. In games you mostly saw an ads every 2 or 3 matches and even if you see one every match it's relatively easy for one person to keep it away from the action. I myself can 2 shot a python with my PLC and commando and anyone who has tried hitting an ads with a PLC knows how difficult it is... .