Teleportation was a solution to the terrible 1-base decision, since you had to reach every apart of the globe from 1 location. If multi-bases are in, then teleportation is not needed.
I despise teleportation, not only because of narrative and world-building reasons and the the massive can of worms it opens, but because of the mechanical implications. (Also, Stargate turned to trash, the only thing saving it was good cast chemistry and banter. And the elder race tropes are in my opinion generally terrible - anything that treats science as magic is)
X-Com games have NOT been just about squad-level tactics. If that is what one is after, there are many games that do it a LOT better (Jagged Alliance 2 for example). Planning and logistics on a grander scale are - to me - the defining aspect of X-Com. Hence, when such is trivilized with magitech teleportation that makes logistic utterly irrelevant (base location does not matter, travel time does not matter, local resource managment does not matter) it leaves a poor taste in my mouth. Also, having a single base, a single point of faliure is a really bad idea for any military group.