I think you're trying to do too many things at once. You have a bunch of creatures, indicating you're going aggro, and the creatures that you do have seem to support that.

However, you also seem to be trying to play control secondary - and while U/B control is really strong, that's not the deck you're trying to make here. Hostage Taker is great in some archetypes, but I don't think it's right for your maindeck in particular.

In general, let's look out what this needs against other widespread decks in the format.

Red - needs a few more combat tricks a la Skullduggery or something else.

Control (UB or WU) - Lookout's Dispersal is your best friend, but even still maybe not enough to warrant a 4-of in the main.

Temur energy - You'll probably be trying to outrace them, so you're gonna need evasion and some kill spells. You can't murder a Bristling Hydra, though, so maybe take some Lightning Strikes to get the ability to hit their face?

I'm not an expert on Standard, though, so please do try it out against other people and see how it works.