This mod rearranges the order in which you unlock weapons, armor, throwables, and melee weapons.
Without this mod, you unlock a majority of weapons within the first 40 levels, which is only about 2% of the total experience required to reach level 100 (no typo, that's one fiftieth).
With this mod, you will unlock worse/lower-tier weapons first, and better/higher-tier weapons near level 100.  This should give you a smooth curve of increasing power as you level.
You will unlock something every level between 1 and 100.

This has not been extensively tested without dlc.  If you don't have all dlc, this may not work as intended.
I cannot guarantee that this will be updated in the future.  As new content is released for Payday, I encourage you to make your own edits to this file.  You can find a list of WeaponIDs updated through Scarface here, and the rest are usually on each weapon's individual wiki page.

This mod requires BLT, which can be found here: BLT Download (just click on the latest .zip that isn't source code)

To install, download and unzip LateWeaponUnlocks.zip.  Copy the extracted folder into your Payday directory's \mods folder.
To disable, go to the main menu ingame --> lua mods --> uncheck LateWeaponUnlocks
To uninstall, delete <payday directory>\mods\LateWeaponUnlocks.

Special thanks to Morerokk from reddit's /r/paydaytheheistmods.  This mod would not have been possible without his help.