I just bought a mouse 4 times more expensive(laser Genius) than my previous one, which I researched and waited 2 weeks for, only to find that you have to press many times harder for both right and left click.
I don't know if you realize but this means tremendous loss of productivity in everything you do!
And some games, like Torchlight 2, have become practically unplayable

I had the cheapest Logitech mouse, which registers clicks with the slightest touch of the finger and is super responsive, but the middle mouse button broke...

Jesus imaginary christ, I had no idea this pressure thing is such a huge factor, I thought the responsiveness of my cheap mouse was ubiquitous.

Is there a specific term for this? How can I tell in the future if other mice have this condition?

You could perhaps mod the switches inside the mouse.

I like the Logitech RX250 btw. Cheap and durable.

Yeah, it seems Logitech is the way to go if they established this standard in the manufacturing process.
Deviating from a certain brand always bites me in the ass, like with motherboards and GPUs.

There is a universal term, AFAIK it's just "pressure" or "force", same as keyboard switches, but makers don't advertise it yet - probably because most mice don't have much to shout about. Mechanical keyboards changed that playing field by specifically advertising activation force and levels of feedback.

It's about the switch that is inside, and a little about the button design. Omron switches are the typical "light touch gaming switches with feedback", but in Razer Imperators for example they have been going flat (no press/repeat presses). The cheaper switches are often more rigid or simply limp (may appear responsive but have no feedback, may go flat fast with high APM). The design affects how much and how long your finger rests on the button (static load), how big of an arc you need to click, how it suits your grip etc.

I like my Steelseries Sensei Raw after two Razers died on me (Deathadder with busted wheel, Imperator with flat Omron switch, I later found out both were features of the designs). So far no news of "features" or switch death in Steelseries, but Sensei is a new model.

The cheaper Steelseries Kana has much stiffer switches than the Sensei, do not recommend it. I ordered three mice and kept the one I liked most.

PS. This is why you always, ALWAYS compare first, then make the final decision.

I've been using a Logitech G5 for a couple of years. I like the adjustable weight and the hand contour suits me. Takes a little bit more pressure than the generic mice I've used in the past - but nothing strenuous. However, I don't play games that require a LOT of mouse clicks/min.

What do you mean, there isn't a single store in which you can try a mouse before you buy it and reviews are obviously completely useless.

The only way I could have avoided(or not be surprised) this or anything like it in the future is if someone randomly mentioned "oh there is this pressure thing nobody ever talks about but you can't know until you actually buy the mouse and try it so it isn't worth mentioning anyway".

Basically I'm forced to buy the exact same mouse I had to avoid wasting any more time/money.

Well it sucks if you can't. Y'see, the stores near here have mice on display (not just the pretty packaging, though that sometimes allows you to try the shape nowadays), and if you order by mail (as I did), you get 14 days to try the product "as you would in a store" and you can return what you don't like for a full refund. Coming from a thrifty family, a blind purchase to me is nothing short of a gamble - gotta inspect the goods!

I've also had success simply asking a shopkeeper if I could try something. Usually it's "you break it, you buy it", but you can try it for free.

You're right about reviews being useless, as they often gloss over basic stuff like this.

PS. The activation force difference was a surprise to me too with Sensei vs Kana. Sensei is what I thought all mice were and have been thus far (and I've tried quite a few), which leads me to believe there was only one switch type for a long time, and only now are there alternatives.

This should be stated everywhere, like it is stated which panel a monitor has or which engine a car has.
Unbelievable.