Blue Monarch
Lonely Heart
Nothing is "cheap," so long as its allowed by the rules. The word "cheap" is a word meant to accuse both a certain strategy and the players who use it. Those players are only trying to maximize their chances of winning, which is what competitive pokemon is all about, with whatever resources are given to them. People should not be criticized for doing whatever it takes, within the rules, to win.
What there is, however, are aspects that can decrease the depth and quality of a meta-game. Communities, like Smogon or PO, decide in their own ways what constitutes the optimal meta-game, and if removing certain aspects improves the metagame, it is done.
Word choice aside, however, you are right in decrying some of the abilities for having a negative effect on the game. Shadow Tag is probably the biggest offender there, and that is why Wobbuffet was rightly banned in previous generations. Chandelure makes it much worse. Thus "best" in terms of advantage gain is "bad" for the quality of the game. I'm reserving judgement on permanent weather, because while it is powerful, there are still enough options within each weather to perpetuate a level of variety.
I'll agree that Sap sipper is a wonderful ability. Azumarill in particular might find some real use for it.
Agreed with the semantics EXCEPT...
Shadow Tag is cheap though :|
It is a HUGE offender and makes something like Wobbuffet and Chandelure quite monstrously broken.
Some objections:
"But things hit harder this gen!"
As opposed to what? Yes Haxorus hits ridiculously hard and Gamefreak has a huge fetish for hard hitting Pokemon this gen apparently, but wasn't Wobbuffet played in ubers and still got away in spite of the harder hitting Pokemon? Besides, you choose who to switch Wobbuffet into and trap them, and unless the other guy had a Shed Shell or have Shadow Tag themselves or maybe U-turn/Volt Switch, they're not escaping the clutches of Wobbuffet anyways. There is NO ONE with brains out there who will switch a Wobbuffet against a Hydreigon, for example.
"But Encore is nerfed for 3 turns!"
You're still helping something to set up, regardless of the turn nerf, 3 turns is all you need to help something set up.
"Good players can counter Chandelure"
No, you can revenge it with stuff like Tyranitar, but you can't counter Shadow Tag Chandelure without taking overspecialised measures. For example, you will need to carry Shed Shell on every Pokemon just to escape one Pokemon from revenge killing something. How is that countering? There is no way to directly switch into Chandelure because Chandelure chooses who to KO and who it doesn't. It's quite simple; you meet Shadow Tag Chandelure, that's the end of the road for you.
"Stealth Rocks chips off 25% HP off Chandelure"
... still a good 4 Pokemon quite possibly revenged.
Now that I got that cleared up...
Yes, Sap Sipper is awesome. Grass immunity is something not to be scorned. Sure, Grass isn't that great of an offensive typing, but it saves you from being, I don't know, Contrary Serperior dead or Leech Seeding Ferrothorns. In fact, that attack boost can make a Sawsbuck an ideal counter to Ferrothorn, dealing considerable damage to Ferrothorn with Jump Kick while switching into a Leech Seed or Power Whip. Gyro Ball I imagine might hurt a bit, and Thunder Wave is no fun.