Since the whole community agrees that it's broken, and there's no opposition, why waste time? This is especially considering the fact that there are a huge number of other issues in the tier we need to deal with. Everyone has been calling for more aggressive tiering and a public suspect would not be helpful in that Would it really kill to just have a council vote?
In addition, we've heard almost no word from the council on whether Latias-mega is broken or not. Could you guys please give your opinions already?
As to your first point, I think you're assuming that a council vote would more or less be synonymous with a ban. While we have not yet voted, I think this is far from a foregone conclusion. We've been discussing Latias-Mega all week since the Garde ban. When I say that the council is divided on whether or not this is banworthy, I'm not exaggerating. We run the full gamut, from those of us who feel that it shouldn't even be suspected at all (much less banned) to those who want to push for one without waiting for a full suspect.
Council votes are meant to be used in extreme circumstances, when something is so unhealthy that it is single-handedly unbalancing the tier. Jirachi, for example, far from being balanced by the more offensive post-tier shift meta, proved to be an incredibly toxic and dominating force with its Happy Hour set following the Hera/Gallade suspect. Gardevoir-Mega was similarly dominating, especially in the post-rachi meta, with most teams having little counterplay to it outside of hoping to trap it with Weavile. These were major cases where a single threat was skewing the meta in a really significant way.
I've seen a lot of posts of people saying that they don't like Latias-Mega and think it should be banned, but I haven't really seen a lot of justification for this. Most of the arguments devolve into "it's fat, it has ways to beat a lot of its counters." That's definitely true. Latias-Mega has a ton of really good sets, and I think it might be banworthy on the basis of its sheer unpredictability. I'm not saying I would vote ban, but I can at least understand the arguments there. However, I haven't seen any convincing arguments that that it is as dramatically unhealthy or is skewing the tier as negatively as the other threats that have warranted such drastic action. I've been playing quite a lot in the post-Garde/Weav meta, and while Latias-Mega makes a pretty good case for being the best 'mon in the tier, the meta as a whole has actually been a lot of fun and I've felt a lot more flexibility with teambuilding than I did in, say, the Gardevoir or Jirachi metas.
As for your second point, I think people are seriously downplaying some of Latias-Mega's issues. It is exceptional when used defensively, and it is a great late-game wincon, but it requires a significant amount of team support to properly sweep. It is super vulnerable to status, in particular Toxic, and even sets with HP Fire/Fighting struggle a lot against most of the bulky Steels (Klefki in particular, but Empoleon, Bronzong, Aggron-Mega and Metagross have all been extremely effective in this meta). Similarly, it has a lot of difficulty breaking through AV Muk, which has spiked heavily in usage following Weavile's ban. It also lacks the immediate firepower of regular Latias, which has the advantage of being able to carry a Z-crystal to punch through threats, and typically has to rely on coverage or on less reliable moves like Stored Power to pressure bulkier foes. It also still struggles against the other Megas in the tier, in particular Altaria, Beedrill, Aggron and Sharpedo.
Of course, it has ways of breaking through all of these counters, which is why I think it still deserves a suspect. It has crazy coverage options, and Reflect Type or Refresh can help it break past some of its vulnerabilities. All of these come at a cost, though. Running Reflect Type or Refresh typically limits you to one attacking move, which means either picking something like Stored Power (which means you have no way of hitting things for reasonable damage without several boosts under your belt and you become completely vulnerable to Dark types), or going with a general neutral move like Ice Beam (which means you have major issues with coverage, no reliable STAB and struggle to break through special walls). You can build around all of these issues with the rest of your team... but again, Latias-Mega just requires a lot more team support to sweep than people seem to be admitting in this thread.
So yeah, I think that there are genuine merits to discussing and possibly suspecting Latias-Mega, but I do not think it is so overwhelming that it needs an immediate council ban.