Similarly to Blarajan (who made a detailed post on the previous page), I didn't play much XY NU (~5 games total) and took up ORAS NU recently for testing, and eventually playing in, SPL, so I guess I have a "different" perspective on things to some extent and within this post, I'll give my input on the current state of the metagame and potential lines of action going into the future.
First off, I believe that the NU meta isn't awful, but it has some room for improvement and if we can figure out how to "improve" NU properly, then it will open up the tier and enhance the quality of it, too. This leads right to the key question: what needs to be altered so that the tier can "improve"? (Note the emphasis on improving the tier. This means banning something prematurely can negatively impact the tier and while this would alter the tier, it would not be the ideal change) The answer to this isn't simple and will vary depending on who you ask, but a majority of people's opinions will have some parallels based on what I've observed so far. Personally, I believe the following Pokemon are controversial, meaning that they at least warrant a formal suspect, if not a ban: Mega-Steelix, Typhlosion, and (maybe) Mega-Camerupt (in this order of priority).
Mega-Steelix is all over the place. People thought Druddigon was popular in BW RU and people believe Landorus-T is too common in late XY/early ORAS OU, which may be the case, but Mega-Steelix in ORAS NU takes it a step further than both of these aforementioned pokemon in their respective metagames. To exemplify this, Mega-Lix was seen on 8/10 SPL teams week 2 and is frequently seen among the higher part of the ladder. Seeing as Mega-Lix is getting this substantial usage, there must be a reason to warrant it, and there is: it is just so good that most teams have little-to-no reason not to use it. Stellar defensive typing, unmatched physical bulk - even without defensive investment, solid special bulk, strong offensive presence, and a movepool that is wide enough to grant it all the necessary tools to make it so dominant in NU are all characteristics of Mega-Lix. Looking at it in a conventional "what checks/counters it" sense, Lix does have a fair amount of answers that are viable in the tier (Seismi, Ludi, Poliwrath, Mantine, Vileplume, Pelipper, Tangela, Prinplup, etc.), but that alone isn't enough to say Steelix isn't banworthy/suspect worthy in NU. The fact of the matter is that it's unhealthy for a metagame to have so much emphasis on 1 threat (see: Pistolero's reference to Primal Groudon in Ubers) and while I don't always like using this term as it is commonly misused by many posters in my experience with suspects, Mega-Steelix is (over-)centralizing due to this abundance of usage and it being consistently effective/worth using over alternatives. A byproduct of centralization is the metagame becoming restricted with the exceptions to this being "innovations" that try to manipulate the limited state of the tier, which some may argue is the case with NU right now and this argument has reasonable support behind it.
TL;DR/overall opinion: Mega Steelix is certainly something to look into due to the arguably toxic effect it has on NU and while I'm not 100% sold that it is banworthy, I am getting there and a suspect would certainly be called-for in the near future.
The other Pokemon that I am sold on being controversial, to some extent, is Typhlosion (I'll save Mega Camel for a later date as I'm still on the fence and it is not a priority). Typhlosion, unlike Mega-Steelix, isn't a tank of amazing proportions, but it's a wall-breaker and potent offensive presence in the tier that may not see anywhere near the usage that Steelix sees, but is still a top threat alongside Steelix and some others. To cut to the chase, handling Typhlosion's powerful special attacks is generally the issue - teams are virtually required to run one of a few things, which can increase or decrease in amount depending on what fits into the team and what doesn't, but the point still stands that Typhloision (and the other specially offensive fire types to a lesser extent) can be restrictive and a pain to deal with. This leads straight to to obvious question of: what can deal with Typhlosion? Well, I'd say the notable checks/counters are: Hariyama, Seismitoad (HP grass can be a thing), Mantine, Lanturn, AV Magmortar, flash fire Flareon/Ninetales (eh), and SDef eviolite Zweilous/Munchlax (wary of Specs Focus Blast). So it's not too small a list, but not all of these fit into offensive teams (the up-and-coming Specs Mantine, AV Hariyama, Seismitoad, and AV Magmortar are the only ones that do so and all of these lack recovery). The way to look at this is to figure out if the lack of surefire, practical checks/counters of Typhloision is enough to make it worthy of a ban/suspect or not. I say yes to a potential future suspect and I am on the fence about it being broken (leaning no), but it's in the eye of the beholder as we all play and view the tier differently.
Sorry if this is sort of long and apologies for any typos or errors as I've type this on my phone.