As stated before, the game runs on an engine built on top of the 1.0 engine, which was released in late 2010, but the actual coding probably started in 2004-2005, as the first tech demo for what became FFXIV (Rapture was the name shown on it) was showcased in 2005. Even with all the changes made to the engine over the course of the 4-5 years prior to 1.0 release, the game was built on the Crystal Tools middleware from SE, which was used for FFXIII, with only a few adjustments for use in XIV, so there were still many limitations on what could be achieved on a technical level.
2.0 (Or ARR) was then re-coded somewhat in the course of 1.5-2 years, but it's not realistic to expect the team could've made drastic changes to the core of the engine in so little time. I'd really like more customization options as well, but as a programmer myself, and having studied some game coding, I know it's not something we can expect unless we get a complete overhaul in the game coding on a future expansion.