As I browse the forums I am actually able to reach here at work, specifically the ones dedicated to Tabula Rasa, I see the same worry and complaint brought up time and time again. Past the 30th level and all the way to the cap of 50, there isn't much of a "carrot" for players. At least that's what I'm reading and I can see what they mean.
In TR, the way the leveling and skills are set up, you're not guaranteed a new skill or even a new level of a skill with every level. You might have to wait 2 or 3 levels before you can get that 5th rank of Polarity Gun for instance. Couple this with the fact that leveling from 30 and up can be a painfully slow process for some due to a lack of upper level content, and you have the exact recipe to make people get bored and stop playing.
There are additions coming though within the next three months that can hopefully keep people playing, at least to the level cap, while a more concrete form of end-game material is worked on. From what I understand, both of the following additions are scheduled to go live by late January, early February. Whether that's soon enough is neither here nor there, I'm not here to speculate on that aspect. I'd rather just bring to light a couple of additional "carrots" that are coming at the beginning of the new year. I could be wrong on the date, so don't hold me to it. We know how nebulous MMO target dates are anyway.
The first order of mid-high level TR improvement is what the development team is calling Personal Armor Units or PAUs. Think of these as a mount of sorts, only with combat abilities. They will be attainable at level 40, and there will be one for each of the level 30 class branches, so 8 in total. They'll be somehow akin to the theme of each class as well. For instance a Guardian will have a hulking tank of a PAU while a Sniper might have a more speedy and frail ranged attacking PAU. It's still unclear how these will really function, but we can likely assume that they'll be far more powerful than an AFS soldier alone, and likely not useable all the time. Hopefully they won't be a once an hour type skill, but more of a high consumable rate thing that a player will need money to use if they wish to place a restraint on its usage.
The second and higher of the planned carrots is something called Command Opportunities. These will be useable at level 50. From what you can read at sites like TenTonHammer, the idea is to give the player a squad of friendly NPCs to have at their exposure for both tough instances and for PvP aid. They're going to be able to be ordered around, but to what extent we don't yet know. We also don't know just how useful they'll be, though the developers say it should help out those players who like to duo or solo but desire a bit more help on some missions.
Also out in the clouded future, hopefully sooner rather than later, Massively has reported that soon Clans will be able to further extend the purpose of Clan Warfare (only prominent form of PvP currently), by allowing them to capture and fight over Control Points. These are essentially alternate bases that are fought over between the players and the Bane right now, and soon added into the mix will be Clan Warfare. The idea I guess is to make some benefits of the economy added to the Clan who controls a CP in order to make the undertaking lucrative. It's a bit silly still to have the last remnants of mankind in-fighting, but let's face it... in a game lik TR PvP is a perfect fit. It could use a lot more fleshing out.
On top of all these things, the team is constantly working on new story missions and instances, loot is being rebalanced to matter a little more so that you'll actually care what you have on your load-out, and every 3 months or so RG and team want to put out a major content update much akin to CoH's long-running practice. And to go one step further, they also plan on releasing a boxed expansion with a new planet and whatnot every year in the fall, like SOE does for EQ2.
In all, I'd say the future is bright if it can deliver on all of these plans. I'm greatly looking forward to a few of the upcoming MMOs, but I can definitely say that I'll always be watching TR and likely subbing and resubbing to it just as I have to so many games over the past few years. It's rough around the edges, but next year I wouldn't be surprised if this little gem is shining brightly like EVE does or CoH, off in the peripheral holding its own and with a hugely loyal fanbase.