Having all alternative announcers and maps be time restricted feels terrible.
It may come as no surprise, but LoL's basic announcer is...bland, boring, and uninteresting. Compare it to a game such as Hots and its myriads of varied announcers along with their broad variety of voice lines, and it's not even a fair comparison.
The announcer is an important part of the MOBA experience. it puts a certain tempo and feel to the actions you take. I remember when the bilgewater event rolled around. It was probably the best time I ever had playing LoL. The GP announcer (along with the Butcher's bridge music) really made all the difference, I felt like I was playing a different game. When the event ended, I did everything I could to keep the announcer around, through mods, files edits, and so on. It's not an understatement to say having this alternate announcer gave me a huge boost in desire to keep playing. Having your game "narrated" by an evil pirate king felt amazing!
Now, three years later, we are seeing the next "big" alternate announcer hit the game (SG Ahri). It may not be as amazing as GP was, but it still feels awesome to play! However, once again, that announcer is limited in time, and when it'll be gone, if we want to keep it around, we'll need to attempt underhanded and unreliable techniques in order to get it back. And we don't even know if it will naturally come back eventually. Heck, GP announcer never came back, and it's been three years.
My point being, you have made a lot of awesome content, such as those two announcer, or butcher's bridge, which was much funnier to play than the howling abyss, imo. It makes me quite sad to see that kind of content being time limited, and probably never coming back. I would buy an announcer pack, even if it cost 1820 RP, without any second thoughts. I would equally buy a skin for a map, even if it had to be 3250 RP.
I just wish I could experience those again, and I would also enjoy SG Ahri not disappearing! (Sorry for any english mistake, I'm not a native speaker!)