How about steaming, rather then boil. Steam may catch the sweetness of the seafood inside and it taste good.
De-veined the shrimp is better but take times to do it. How if you just cut (wiht scissor) through the back of the shrimp and leaves the head and tail intact. Cut the back will halp de-vein the shrimp too, head and tail intact will enhance the taste and good in presentation.
How about put some herbs and other spices to make it tastier in your boil or steam seafood such as celery stalks, carrot and onion as it will add more sweetness into the seafood.
Asian style cooking: add ginger and garlic duirng boiling or steaming. Sprinkle with white wine after it finsihed with boiling (before putting them into the ice tray) will make it tastier.
More complicated but tastier recipe: add shallots (golden shallots is more preferable, slice thinly), sprigs of spring onion (whole), pineapple slices (2 slice only to enhance ths eafood flavor and soften the shrimp skin), whole kernel of black pepper, a bit sugar to taste and salt.
If you like Crab Claws (the most meat in the crab), just boil them, cracked the shell, leaves the meat intact, cover with Flour+egg+maizena+salt, freeze for 1 hour, then steam it (in a bowl or cover them with all. foil) for about 15 minutes. It will taste good.]
Good Luck Henry.