i think you're gonna get some comments about 'where's the caustics?' or something to that extent... it would help the shadow be more defined but also softer where it needs to be...

the one thing that pops into my head at the moment is that down towards the base of the glass, the shadow should be darker (and there should be a slight highlight of light around the end of the glass base where that shadow begins)

it looks like you've got your IOR about right, cause the refractions change nicely with the thickness of the glass. so i'd say it's a success.