have had with Hydra's

If the incoming aphid nerf is as minimal as expected, better get used to it.

With the rise of a non-LOS, high damage, fast reload weapon Pixonic more or less rendered every knife fighter useless (besides suicide-rushing a beacon).

Given that most bots carrying Aphids have a low HP pool (Geps and Pattons), hydras are actually a good counter to them.

I use Hydras on a bot or two, with the principle of "softening" a target before knife fighting. Also, I use it with the purpose of covering my retreat when necessary. Absolutely never as a primary weapon

First: the leaver is more annoying than even the worst frankenstein natasha.

Second: I assume you dont play in gold tier yet? A Hydra Fujin (or a Spiral Hydra Griff) who starts supressing red Aphid Bots right from the start can be an extremely valuable addition to your team...

Yeah right, if that Hydra Fujin crawls in the most far away, safe-looking corner, then you deffo have a point.

Tbh I just watched one yesterday on Dead City (we were teamed against a 4 man clan squad - 3 of them started with Aphid Pattons - which basically renders shield bots useless, because they cant defend from different directions) - and this guy was absolutely amazing - he knew the exact angles or whatever, and as soon as a Patton showed himself (e.g. lobbing his aphids) he started hitting them - effectively flushing them out of cover or into retreat - all three were taken out in the process from our midrangers.

Before that show of skill I was also convinced that Hydras are useless

This, I agree. But I can probably count on one hand the good hydra users I have seen who are great at curving shots around walls. I have faced one before. But that's in my 1000+ games. We are all pretty safe from hydras. 

At least the hydra exists, otherwise there would probally be no real good counter to aphid on mediums or heavy

I must be playing against a whole different type of opponent...In my experience playing in mid-gold, they're annoying as hell. In so many matches I've been in, trying to hide behind cover while there are hyra fujins or griffin hydra/spirals firing on you is almost pointless. Unless the cover you're behind is tall AND wide, and the hydra wielding user is far away or at a very poor angle, they can almost always angle it such that it curves around the cover.

Plus, if you're in a shielded bot, shooting hydras at an angle as close to perpendicular as possible to your shield, the missiles are almost guaranteed either go around, or over, your shield. If you're in range, you can't outrun them in a light bot either. They may not do much damage outright, but they can chip away at your health fast enough to kill a fury in about 5-7 weapon cycles. Much faster if there are 2 or more missile(hydra/spiral) bots targeting you.

It annoyed me so much that I went and got myself a few. While I was never able to deal more than 300k plus in a single match using just the missile bots, 300k plus is the combined health pool of 2-3 level 9 bots...

Do you consider Tulums useless? Many popular mid range setups include Tulums. The Hydra has 815 DPS compared to the Tulums 966 DPS, but it is a homing missile and has 100m more range. If you want a midrange medium weapon, Hydra is really the best option in a rocket setup (only Molot has more DPS but requires you to be in line of sight). 

I for example run a rocket Golem with Trident, Hydra and Pin, and it's pretty effective in lower tiers.

The Hydra is a mind weapon...it fills you with frustration and hate. Then you start doing things you don't normally do...The game has only one psy weapon and this is it.

Or the Treb. You always look across the field hoping that you are not on the receiving end.

It needs more umph

Played a match earlier that towards the end left me and one ally against THREE hydra/spiral griffs on the opposing team. Yes, their damage per shot might be low, but believe me, the almost constant screen-shaking pounding that came my way for the remainder of the game was as effective as it was annoying. We were completely pinned down and ended up losing.

Granted that was an extreme and rare example and whilst I don't have the patience for it, it showed that they can serve a purpose if used properly.

I've done well over 500k in tri-hydra fujin lv9s

It is a sophisticated bot because you have a very important shield to your team and you can't afford to miss. Hydras do take practice, it's kind of like throwing a bowling ball, you have to curve it and consider cover, distance etc.

I'm actually really bothered by this.
Especially the quitting of matches instantly due to seeing a certain weapon that you somehow deemed useless. That is ignorance at its finest.

I bought a hydra once after getting annoyed by the hassling I was getting from them. Soon I realized that it wasn't all I thought it was going to be, I couldn't hit much with it initially and the damage sure wasn't what I was expecting. I retired it quickly and moved on.
However, further down the line once I got my Rhino and was getting frustrated with not being able to lower my shield to fire orkans, tarans, or tulumbas due to getting lit up instantly, I got another hydra and started putting them to use.

This is indeed not a bad setup at all! As I worked the outskirts of the maps I was able to fire my hydras between straight line shield up runs. Upon running into the enemy I would sit behind my shield and chip away with my magnums, no longer tempted to lower the shield just to fire my hydras I would actually last longer. If they ducked behind cover I would unload the hydras on them. It worked great.
The annoyance factor is the biggest key in my opinion. I knew that people were looking at me shaking their heads but I was proud of my unorthodox ways. Maybe once they saw my damage and beacon caps........IF THEY DIDNT LEAVE THE @#$%ing MATCH!!!!!!!.....then they would have opened their eyes.

Just a thought. With that I will end my rant about your rant and thank you for your time.

EDIT: Just to show I am not spewing BS about it. (I realize that I was a lot lower level then also but I'm sure I could still put it to worthwhile use)