I have three of these "big gun" creatures, which are around the size of vehicles in Epic. They are good proxies for exocrines. In fact, they look lean and mean, a lot better than the "slug" design of the original Epic miniatures.
Here is a comparison of the exocrine proxy versus a Forge World Tau Devifish APC. It's the perfect size for a medium vehicle.
A size comparison with classic Tyranid warriors. These "exocrines" will provide much needed armoured fire support for an Epic Tyranid army.
I also have some bigger creatures with large scything talons and lobster-like claws. These are good for Haruspexes, large close-combat monsters. Again, they fit the current Tyranid design much better than the old Epic "slugs".
A comparison with the exocrine proxy showing the slightly larger size.
Don't worry, soon I'll be showing more pictures of painted Tyranid units. I'm just still working on getting a playable army ready.