Which reminds me: If Icefrog is so interested in competitive viability and diversity, why doesn't he look at making a more interesting long-term stealth mechanic that's less flat and "buy x to counter or get stomped"? That's not interesting, and as I understand it the super stealth champs kinda suck in competitive play.
Like RCIX said, invis heroes are used commonly in DotA 2 games.
Broodmother, Bounty Hunter, and yes, even Clinkz appear commonly. I saw Clinkz just the other day in a big finals game, I don't remember the tournament but his team stomped them. Clinkz is an amazing hero because he's one of the few carries that can push towers like a rockstar, giving him a whole new role that's extremely hard to counter with his invis and speed. I expect Nyx Assassin to be used a lot in the upcoming "The International 2" Tournament hosted by Valve.
On the contrary to what you're saying, countering invis heroes in DotA is much harder than in League. In League you have your tankiest hero buy an oracle and you're done with it. You can even destroy wards, and therefore enemy map vision and control with this item. EVEN if it only saw wards, it would still probably be worth the 400 gold investment, because wards are such a huge part of both games. So in League, here you have this cheap item that detects invis so easy.
I haven't been keeping up with the competitive scene, but tell me, how often are Evelyn, Twitch, Shaco, and other invis heroes used? You complain about DotA's anti-invis mechanics, but invisible heroes are used all the time in competitive DotA. How often are they used in LoL?
Every anti-invis mechanic in DotA has some huge drawback (unlike Oracles). For one thing, they ALL take up an inventory slot. This isn't that big of a deal in LoL because of the way the items work. In LoL, the items scale up, meaning the more you pay, the better the item. With this mechanic, the best items are the most expensive.
In DotA, the items scale down, which means that cheaper items are more cost efficient. This means that the more full your inventory is, in general, the more effective you are. It also keeps games much more balanced and makes comebacks more likely because that carry may have items, that while much better than yours, aren't nearly as cost effective as yours.
So anyway, every anti-invis item all take up an important inventory slot that you could have been using for something else more important.
Dust, the cheapest anti-invis alternative, costs 180 gold, and comes with 2 charges. It reveals invis when used in a wide area around you, however the effect wears off quickly. If the invis hero can evade you until it wears off, he can escape. It also has a huge cooldown (60 seconds), so you can only use it once in a battle. This means multiple people on your team might need to carry dust in order to counter the invis hero, wasting multiple item spots.
Sentry Wards are expensive, and also take up an item spot. They are stationary meaning the enemy can walk out of range and be gone. They are my personal favorite counter because unlike dust, you have the opportunity to catch the invis hero by surprise if he walks in range (proactively), instead of using it after he attacks like dust (reactively). These are my anti-invis item of choice.
Gems cost 750 gold, and they basically work like Oracles. However, there's a huge drawback: If the hero holding the Gem dies, it drops on the ground. The enemy team can kill your gem, or even pick it up and use it against you! Also takes up an inventory spot unlike oracles.
Necronomican level 3 is another counter, but it costs quit a bit of gold, and has a cooldown twice the length of its duration. The minions can be killed and to use it correctly requires quite a bit of micro.
So you see, every anti-invis item in DotA has some major drawback. Aside from the small gold cost, what is the drawback to Oracles? I don't know how invis heroes are now in LoL, but when I played they were useless. If you want to talk to 1 company about improving the quality of game for invis characters, it's most likely Riot
I'll discuss MF and Kat vs. Potm and WR in my next post. Thanks for the discussion btw, I hope I haven't upset anyone.