Its a tough comparison as its a faction grind vs a skill grind, however, I do agree the Underworld Missions could use some love. They are dull pizza runs back and forth from NPC to NPC that feels unrewarding and lackluster for gameplay.
Now correct me if I am wrong but I havent completed the faction grind on Restoration as of yet but you get 50 UWFP per mission for Tatooine, 25 UWFP on Naboo, 25 UWFP on Lok, 30 UWFP on Yavin (PVP) and 25 UWFP for PVE and 35 UWFP (PVP) and 25 UWFP for PVE on Dathomir if memory serves.
You can also collect Contraband from NPCs by redialing them after death (this was broken when Restoration launched, unknown if they fixed) or by doing space as a Smuggler. Contraband can be sold to a couple different NPC's throughout the galaxy, I know of three, one one Yavin, one one Tatooine and one on Corellia.
Now here's the problem I have experienced. Tatooine contraband is worth 100 UWFP, Corellia and Naboo if I remember right were only worth 25 or 35 and then its not worth to even bother running Contraband at all. You make more Reputation and more money running the normal pizza runs rather than using your collected Illicit Goods.
It would be nice to see each Tier receive a contraband NPC (or to be known if there are more than three) to sell to or run Contraband missions with making it useful and profitable. Each tier respectfully should be worth double the UWFP if you run a Contraband mission vs a normal pizza run. This will put the Illicit goods to use and help ease the grind.
These missions should also be worth more Credits than their counter parts by not having to pay the "Upfront Fee" since you are bringing the Contraband yourself not buying and delivering from the NPC.
Id also like to see fresh new random locations for both PvE and PvP missions Tier 4 and 5 to keep it interesting and enjoyable instead of mindlessly auto driving to your destination.
I will take the time to make a separate Player Voice about the changes Id like to see to smuggler including more additions to UWF if the player base sees interest in it.