We give each LEGO Ideas project that enters the LEGO Review a thorough and fair analysis of whether it is possible to release. This was the first opportunity we had to seriously consider a project based on Star Wars, an existing LEGO license. So, we're applying what we've learned from this case. For further explanation, please see this section within the Guidelines and House Rules.
The decision on the UCS Sandcrawler specifically applies to this project. As long as other projects meet the requirements of the Guidelines and House Rules, we will allow them to be considered on LEGO Ideas.