Disclaimers: This is my point of view, and you probably won't agree with everything. IL Skyblock is great however, a few things should change in my opinion.
Ranks;
There are cool ranks, yet I think that there are 2 ranks that shouldn't exist (Specialist and Ultra). The upgrade from Astronaut to Specialist brings you /feed and 1 more vault (there are more perks but those are the most useful ones). Is it really worth spending money on? Ultra upgrade has heal, nick and stack (you still can't grind zpm even with this rank).
The Comet and Space rank should have more quality of life perks, for the price you pay, you should have more unique advantages.
On Purchase;
I'll take as an example Comet, the 130$ rank. When you buy it, you only get 20k in-game! It's less than an inventory of chickens. I know that 20k might be a lot when you start, but after a week, it's nothing. You also get 6 common keys, where you can win spawners and OP swords. The problem with these crates is that you can win 500$ or Temp Fly which is useless! You can also win golden apples and kits (besides Skygod+ they aren't so good). The other crates would be a lot better without what I just mentioned. Correct me if I'm wrong, but no one has ever won a rank in these crates. Knowing the odds of everything would be useful.
Starting;
Starting Skyblock without a rank is really hard, and it's a problem. I'm sure with an easier start, there would be more people on Skyblock. Not everyone wants to mine a cobblestone generator for 30h to get their first spawner and sword.
@GucciRetro gave me a great idea earlier this morning, what if Skyblock had better jobs/challenges which would give you money. For example, having challenges as mine 50 cobblestones to receive 10k would make starting easier. (Most of the veterans and advance player help the new players when they start, but when it reset, no one can really help)
Unique;
IL Skyblock is missing something that would make it more special. Every reset, you're just doing the same thing over and over. It's just ''Minecraft in the sky'' as sans said. If there would be cooler challenges that take a lot of time to carry out (that would give you a good reward) and a real reason to be in the top 10 islands (could be better stuff next reset, free rank upgrade to 1 member in the top 3 islands, etc) it would change everything! A lot of people leave until a next reset because there's no goal to reach and no challenge anymore.
Reset;
There are not enough resets in my opinion, and they should be occurring at a specific time determined before the reset (every 4/5/6 months)
Scammers;
No one really likes scammers, most of the time they come on Skyblock for a short period and leave. Many people think that it should be slightly punishable. They could lose the money they scammed as an example. Small punishments like that would make them understand that it's not something they should be doing.
As Esteban told me, before buying something in a chest that is 100k+, it should warn you and tell you the amount of money you're spending. That would reduce scams drastically.
Nonetheless, IL Skyblock has one of the best communities in Minecraft, and the server is still a great one! Those are minor issues.