In the "Mods" tab of the client, the width of the dropdown with the two different versions of WoW is not wide enough to show enough information to know which version you are currently looking at. There's plenty of screen real estate in the client to extend it out so it shows the full path by default, and/or make it so the user can drag it out to make it a lot wider than it is.

It would also be great if instead of seeing the folder path, we could see a nickname we choose, like WoW or WoW Classic, or perhaps a version nickname for Minecraft users. Anything but the full folder path!

Thanks!

Both Minecraft and Java have changed a lot over the years and things have changed.

When you launch a minecraft modpack through the Twitch Client, it will automatically assign a couple of flags a user has no control over. One of them being the -xms flag which is always set to 256m and the -XX:PermSize flag which is also set to 256m.

First of all, PermSize has been deprecated with the release of Java 8, meaning it has been ignored since even before Amazon acquired Curse and fused it with Twitch.
PermSize has been replaced with the new Metaspace. I highly recommend setting the flag -XX:MetaspaceSize and tuning it to 256m instead.
I also recommend allowing a user to choose to set the -xms flag.
There are a couple of reasons for this:

When Java Virtual Machines periodically garbage clean, they attempt to scan and reduce anything towards the set xms value. This can cause seconds long freezes if it involves a modpack.
Modern minecraft requires 2G RAM to play, so it will even affect vanilla. Even if you don't want users to set the flag exactly, I highly recommend raising it to 1 or 2G since this will reduce lag experienced during these global gc scans. (though some users may want to raise it to 4G if the pack is very large and thus requires a lot of stuff to remain loaded in memory)
You can, like you did with the xmx value, limit the amount a user can set it to, if programmed properly. Your client is capable of detecting how much RAM is installed, you can use this to for example define what the limit of the slider will be on the xms as well.

I also need to inform you that minecraft vanilla itself has jvm arguments set by mojang. These arguments are: -XX:+UnlockExperimentalVMOptions -XX:+UseG1GC -XX:G1NewSizePercent=20 -XX:G1ReservePercent=20 -XX:MaxGCPauseMillis=50 -XX:G1HeapRegionSize=32M

None of them appear (by default) in the 'additional arguments' tab and in fact if you don't fill any in, these will be removed completely when the game is launched. This can cause a lot of issues. I recommend adding these (and allowing users to change them if nessecary) in the additional arguments tab if the additional arguments option is empty.

I also recommend adding the -version:1.8+ flag to additional arguments by default. This way, if the client has a java 8 version installed that is in version higher than the included one, JVM will prefer to use that one instead.

If you have questions about the arguments, please have a look here:
https://docs.oracle.com/javase/8/docs/technotes/tools/windows/java.html

Thank you for your time, reading and understanding.

The new one looks like simplified garbage. Make sure to leave your reasons in the comments. 128 people voted for the old improvement and CurseForge didn't even consider it and just declined it. Starting a new one until they at least make the new site functional.
~Too much white space takes up the screen and is not utilized properly, leading to my next point. Text is too small, making this abundantly obvious. The UI looks like it's trying to fit into a phone screen, a device that doesn't use mods at all. This makes everything look awful from the notifications to the mod pages themselves.
~No text highlights like the old UI. Combined with the small text, it's harder to tell what exactly you're clicking on.
~Toolbar is nonexistent. Why get rid of something that worked perfectly fine? Why is the feedback at the bottom of the page instead of the top where everyone can read it? Are you trying to shield yourselves from any criticism?
~Notifications lead to the wrong version of a file. I want to download the main .jar file of a mod, and I get deof/API file instead of the one that everyone is going to use. Trying to find the right Minecraft version of a mod is insanely difficult to do, unlike in the old layout where it was neat and organized and wasn't shoved away to make room for the 3 files I don't need. This makes the files tab for mods confusing. It needs to stop assuming the mod files I want and just list all the mods like it did before. Files need 5 seconds to download? Why? Now you're purposely trying to irritate everyone using the site.
~If you're designers are somehow attached to this ****** layout, could you at least enable the old design and keep the new one? The old notifications are still active and that's the only part of the site I'm willing to use.

Post any ideas in the comments of issues I missed.

CurseForge is knowingly and purposely trying to **** off it's userbase by refusing to listen to what the users want.