BurningMan
fueled by beer
There is exactly one reason to use Entei in OU and that is if you are stubborn enough to think that having a tiny niche with Sacred Fire makes it suddenly viable. There is a reason that Entei was RU last Gen and NU the Gen before. There are just so many better Fire types to use that all have a useful secondary typing, better abilities, better movepools and better stats.I don't think that a Stealth Rock weakness should be taken into account too much when ranking Pokemon. Although being SR weak does imply that a mon needs support to keep them away, I'd argue that this should fall under support for the whole team. Every team would have hazard removal in high-level play, so saying that a certain mon can't be S rank or A rank because it needs hazard support is kinda moot.
Also, I posted this a few pages ago:
It was ignored. Thoughts on Entei, everyone?
Lets look at its typing first you claim that it is excellent, but i completly dissagre it is SR weak which is bad but not crippeling, the real problem is that it lacks a useful set of resistances and is weak to a ton of common attacking types almost every attacker in OU has a way to hit it for SE damage or hits at least neutral with its Stabs except for a few Pokemon, but this essentially holds true for every Pokemon in the game and isn't in any way outstanding. Fire is a very good coverage move, but not a great Stab as there are just no types that can deal with all of its resists at once and even if there were Entei propably wouldn't have it because of its rather shallow movepool.
Which brings me to my second point its move pool which is just awful outside of two exceptions in Sacred Fire and Extreme Speed, it has no good boosting moves, no outstanding support moves and the worst of all not even decent coverage moves, for gods sake its best coverage moves are unstabed Iron head and Stone Edge or a Hidden Power coming from a uninvested 90 base SpA and thats it sure Sacred Fire makes physical mons think twice upon switching in but there are just so many Pokemon that can come in without much hesitation regardless of Sacred Fires burn chance. It has no way to hurt Water or Dragon types and almost every decent team got something that is able to stop it in its tracks.
The final nail in its coffin are that its stats are all around good, but in no way exceptional. 115 base attack and 100 base speed are ok, but nothing outstanding for OU standarts where the Pokemon are either blazingly fast or hit insanely hard and sometimes even both at the same time. 115/85/75 is great bulk for an offensive Pokemon, but when you are weak to all hazards and have so easily exploitable weaknesses that is going to put in in a different perspective. it stats suggest Tank, but it just can't take that role with its weak typing and lack of support moves.