The way that the Lore missions have been organized a new character can level to RA LH3 by the end of the Romulan mission series. Unfortunately, the player would not be able to access the Borg sector missions until he/she completes all of the Cardassian sector missions. This means that a player can receive a prompt that Borg Sector missions are available to him/her upon promotion to RA LH3 but the player will NOT be able to access them until completing the Cardassian missions.
Basically, the game progression needs to be tuned better with skill points adjusted accordingly. I believe that the problem probably occurred when the Reman weekly series was integrated into the Romulan story line.
agreed, the mission scales but the reward doesn't, also with that the skill point rewards are way too big, i am captain 4 now and each time i do a story mission i level. the biggest issue i see, is that by doing only story missions you will streak through the levels with a lot more story but not much in lines of progression left. also, by the time you start getting higher level you need to be sure you picked up components to have decent gear. otherwise with drops and mission rewareds your character isn't ready for higher levels.
Regardless of the amount the XP gets decreased for the linear progreession, the mission rewards will still need to be adjusted to make it worth while. Since adding the "featured episodes" into that progression you are way beyond most of the rewards by the time you get to most of the missions in just the regulus sector, not to mention beyond. Factor in the XP from Doff missions (even now that they have been reduced from the 1.5-2k skill points i was getting from quite a few missions before the last patch) and the XP is way out of control for the way things are currently set up.