Frankly, FFG could have very easily gone the "stats are Damage 6, Crit 2, Breach 1, Sunder and that's it!" with zero options for modification of the focusing crystal itself. After, it's the general tact that WEG and WotC took with lightsabers, in that they had a set damage value and the only way to improve that damage value was through external means, such as the Lightsaber Combat power in WEG, or WotC's approach of a blend of feats, class abilities (OCR/RCR) and talents (Saga Edition), and the only complaint was that the base lightsaber in and of itself was fairly sub-par compared to blasters in terms of damage (particularly the d20 versions, though those at least got to bypass DR and object hardness which helped to some extent).
As was pointed out repeatedly on the Beta forums, there's zilch in the canon or EU/Legends about Jedi modifying the crystal to get better performance. And there were posters there that were going to disallow crystals to be modified as a house rule for their games, meaning that whatever the base stats of your crystal was, that's all you got.