What are you mainly looking to get out of it?
with the t5i you are still getting a relatively dated sensor (performs similarly to the canon 7D sensor)
Going for a newer canon rebel will be more for if you want better video capabilities and plan to use something like the magic lantern firmware.
If you do not do more automated tasks, e.g., custom large scale bracketing, for example, if you want to do something like a focus bracketed HDR (combining 100-200+ images) or other more esoteric tasks, then a t5i may be useful
If your main reason for upgrading, is better image quality, and your main focus is still images, then the Nikon D5300 will be a very good choice, you will get far better image quality, and raw files that you can push much further, and recover more highlights.
The D5300 will give you far better raw files than any of the canon digital rebel cameras.
The issue with canon is that they have largely neglected their more budget friendly line of camera by using the same sensor for over 7 years and just doing things like improving the supporting components such as ADC’s and other random parts to squeeze out a slightly better signal to noise ratio, but nothing major.
Nikon has been upgrading their upgrading their budget line more frequently. while their video capabilities are still not anywhere near even the entry level canon cameras running magic lantern, they are still good for basic recording.
(overall, if don’t care much for video, and don’t care at all for scripting and writing custom applications for your camera, (and focus primarily on image quality, then the D5300 is a great choice.) review: http://www.dpreview.com/reviews/nikon-d5300
If you have a lot of money in canon lenses, and cannot recoup the money by selling them (non full frame lenses lose their value quickly), then you may have to move to a camera such as the 70D