TBH, I doubt it wouldn't make much of a difference. From what I've read, the main barrier to progress wasn't Cixi in particular - she was, depending whose account you accept, an ill-informed rubber stamp to a greater or lesser degree.
The main barrier to progress was the Ironhat faction at court, composed of Manchu princes and high-ranking functionaries. And, to a similar extent, the entire archaic system rotating around a figurehead emperor.
If you want the reforms to succeed - which I'm presuming you do, this being ah.com

- you'd need much more than just Cixi's death.
What you'd really need would be a) the reforms to have less foreign involvement - as far as I'm aware, the Japanese had a hand in them, which was made public and immediately raised heckles at the Manchu court. b) You would need the emperor's position to be much stronger vis-a-vis the court itself. c) the reforms should take place at a slower pace, over a longer period of time. If I remember correctly, it was the suddenness of the reforms that prompted a lot of the anger Guangxu had to face.
You would also need an earlier liberalisation of the laws regarding Manchu-Han co-operation. Anti-Manchu sentiment was always going to be a destabilising factor as long as the Han were actively excluded from the affairs of government. This was changing slowly - too slowly. Guangxu could have achieved a lot of public backing by liberalising the relationship at an earlier stage. though, then again, that in itself could have prompted a backlash.
In addition, perhaps earlier military reforms might give the emperor a well trained, modern equipped army at his personal disposal he could use to crush dissent from the Manchu princes? We're speaking about a court that was so hidebound in Confucian tradition, any modernisation would cause trouble for the instigator. The only way to force such reforms through might well have been at the point of a bayonet.