This is partially a suggestion for new ship skins, and also a possible option for those that may not get the Galaxy X skin. I know no official word on the status of the Galaxy X has been made, so just consider this a suggestion/feedback thread.
A potential Galaxy X ship skin alternative could be the Niagara class ship. This ship was featured in the TNG episode "Best of Both Worlds", Part 2. It was a floating wreck in that episode, but later was listed in Star Trek Encyclopedia with a full schematic. The overal hull is a mix of two known ships, with some hybrid part that mix three ships. The Engineering section is from an Ambassador class ship, the nacelles are from the Galaxy class ship. The pylons, neck, and saucer section are a mix of Ambassador and Galaxy designs that show a progression from older to newer design. This class would be simular, but not quite as advanced as the Galaxy X. It could still be an option for those of us that would enjoy a three nacelle Tier 5 ship.
The Nebula class has been mentioned, though no official word has been made to my knowledge. I am not as interested in this class for the same reasons I do not want an Excelsior class. Both of these classes were go between designs that were generally not great sucesses. The Excelsior was not economically sound according to TNG Technical Manual. It is noted that the base hull did prove valuable in later years for other projects. The Nebula also was a go between to allow newer designs to be utilized while not quite completed. The Galaxy class saucer was ready before the engineering and neck sections. To help test the saucer design the Nebula class was made. It was hoped that this class would serve as a tactical and/or research variant. The ship saddly lacked in fire power due to energy output which was corrected in the Galaxy class design. The Nebula class was refitted and redsigned a few times after the Galaxy class had been put into production, but it never fully met expectations. Still the Nebula could be a decent T4 or T5 option, though I say more likely T4.
My only other suggestion is for those that might like a Federation Carrier. Two ship names, the 'Curry' and 'Raging Queen', are mentioned as official Fed Carrier designs. Simular to the Oberth class in looks, they had several launch bays in the saucer and engineering hull sections. Down side is that minimal energy weapons were used, and no mention of torpedoes was listed. I can only assume that these ship were support based ship, that required escorts to function. This would not make them equal to the Klingon carrier which can hold its own with ships launched. It does fit with Federation tactics though. Fed ships support each other, while klingons will work alone or in small group unless it is proven honorable. This could be an interesting Tactical/Science variant, so I still suggest it for consideration.
All three classes can be found at the Starship Schematic Database -http://www.shipschematics.net/startrek/index.php
I only suggest these ship classes due to their use in licensed CBS/Paramount material. I leave new designs up to Cryptic, though I hope they will allow players to 'comment' on designs. If the majority of players dislike a design, then Cryptic will not profit from it.
They may only be cosmetic, but how one looks in a game is just as important as what they can do. It is a social experience and allows personal connection, and if looks do not matter then why not just maike the game text only. Probably be hard to collect a monthly fee for that though.
So I hope my suggestions might spark some ideas, maybe some conversation. I do not expect these things to happen, but I look forward to what might come from them.