1) To get rid of bloat, get Link2SD. Freeze any app you consider bloat. Run the phone for about a week. If any problems show up, you can unfreeze the app. Then freeze the next one, and so on. Once you have all the apps that don't cause a problem frozen you can uninstall them. (Don't forget to clear cache and data on any app before you uninstall it.)
2) As far as ROMS go, most of what most people change ROMs for can be done by installing apps. You don't like the look of your homepages? You want more than one 5-app row on the bottom? Install a different launcher.
You don't like the text app? The KitKat text app (Messaging) is available for download. You don't like the wallpaper? Change it. (Mine is almost always to do with the nearest holiday or event - it's now the back of a dollar bill, in memory of the ones Uncle Sam is going to take from me on April 15th.)
Install Xposed and look at some of the modules it has available (look on the website - there are a lot more than what the app shows). You can do a lot with it that would take a new theme, or even a new ROM, to do.
But if there's a ROM you really want, install a custom recovery first - TWRP is easy to use. Back up your current ROM. Then flash the new one. If, after trying it, you don't like it, back it up (you never know how you'll feel next month) and restore the backup of the original. About the only reason I see for changing ROMs is that the new ROM gives me something that the old one didn't, that I want, and that I can't get from an app. Otherwise it's like getting your car repainted - it's new lipstick on the same old pig.