No, not really. It was Untiered / ZU / (PU) four gens in a row since XY, and its Mega form was only in RU in XY, and NU in SM.
Since it's outclassed as an offensive Spiker in its counterpart Froslass, it really isn't that of a good Pokémon. Not only does it have a terrible defensive typing, but it also has 80 base stats all around, making it terrible in anything bulk related. Even with Ice Body, heavy focus on Def and SpA it won't be that good. If you're that desperate to make it a nice Physical wall, you could use Chilly Reception in tiers where Slowking is available. However, it is a pretty nice offensive Spiker in Gen 9 ZU, which makes it somewhat good. Here's some nice opinions on Glalie in the ZU Viability Rankings.
>- (SV ZU) Spikes is broken, Glalie has spikes while being a super scary Pokémon in its own right thanks to its great coverage and ability to go either special or physical which makes it harder to scout and Tera Ground is also really damn strong. Bulk is nothing to scoff at either, seems higher then it is right now.
>- (SV ZU) Spiker that can threaten out Toedscool. Yes, It's hard to get on the field but specially offensive Ice Types are really good right now due to constant pressure being placed on the psychics throughout the game, and Ice Typing basically going unresisted otherwise.
Some more stuff about Mega Glalie:
>- (XY RU) Mega Glalie gains an amazing ability in Refrigerate and high offensive stats when it Mega Evolves, becoming a potent wallbreaker that's able to destroy defensive cores, as well as a great Speed tier, allowing it to outspeed the likes of Meloetta and Sigilyph. Mega Glalie also offers utility with Spikes, which means that it even if it may be walled, it will not be useless. Furthermore, Mega Glalie has access to a very important priority move in Ice Shard, which allows it to revenge kill many important threats in RU such as Flygon and Virizion. Unfortunately, Mega Glalie's horrid defensive typing and average defensive stats leave it weak to common Fire- and Steel-types such as Emboar and Escavalier. In addition, Mega Glalie is extremely easy to wear down due to its vulnerability to entry hazards and the recoil damage that it inflicts on itself with Double-Edge. Mega Glalie's mediocre Speed tier before it Mega Evolves also means that it has a very difficult time switching in safely.
TLDR; Glalie is completely outclassed by Froslass which is probably outclassed by another hazard setter that I don't know of. Froslass also is immune to Rapid Spin and Taunt, which is amazing for a hazard setter. Mega Glalie was somewhat good in its own tier if you could get it Mega Evolved and not die with its mediocre Speed tier before it Mega Evolved.
Source (Pre-DLC SV ZU Viability Rankings)
Source (Glalie Viability Description)
