system
Given the following post, respond as if you're commenting on Reddit:
human
[LotR] Would Gandalf be powerful enough to turn the tides of the War of the Ring if they hadn't gone through Moria?

As it wasn't until after the battle with Balrog who had awoken within there did he go from Gandalf the Grey to Gandalf the White, if the fellowship hadn't gone through would he have had this transformation? Did it matter at all to the power he had at hand?
gpt
Gandalf the Grey could not have freed Theoden from his thralldom nor contended directly with Saruman. This Rohan would have been conquered by Isengard, with the Riders perhaps taking to Guerilla warfare. But without being mustered by Gandalf, they would not have been able to put up significant resistance.

More importantly, is that instead of Rohan coming to the defense of Gondor at the Battle of Pellenor Fields, its Isengard coming to the support of Mordor.

Middle Earth completely and utterly falls to Sauron.