How complicated is replacing the left inner tie rod end on 2013 Ford Escape SEL?

I'd say as long as you have an inner tie rod tool, you should be in the clear. Most inner tie rod jobs entail similar things, so I'd go for it. Just make sure you gent an alignment after you change it because you have to remove your outer tie rod and that'll mess up your toe adjustment on your car. You can do a decent toe adjustment yourself with a tape measure if you think you're good enough ;)