is this Sliver EDH deck good?

You've got a couple duplicated cards to fix:

2x [Predatory Sliver]
2x [Winged Sliver]

The [Hivestone] is rathr redundant ... almost all your creatures are ALREADY slivers; there's only three creatures it could benefit.

You would benefit a lot from more-flexible land choices. For example, the Triple-color lands from Shards of Alara (e.g. [Crumbling Necropolis], U-B-R). Or more "any color" lands (e.g. [Cavern of Souls] from Avacyn Restored; [Rupture Spire] from several sets; [Transguild Promenade] from Return to Ravnica; and a few more). Even some "spend one to get one" lands, like Oath's [Holdout Settlement] (pay {1}, get 1 mana of any color) could be useful.

And especially with a 5-color Commander, the [Command Tower] (multiple sets; generates 1 of any color from your commander's color identity) would be an excellent choice.

...

For artifacts, still focussing on mana generation and flexibility, a [Chromatic Lantern] is IMO a MUST-have for any 3+ color deck, as it not only generates 1 mana of any color itself, it gives ALL your lands the ability to tap for any color. Even lands that normally generate NO mana (e.g. [Maze of Ith]).

Similarly, the [Commander's Sphere] is very useful; it generates one mana of any color in your Commander's color identity. For you, that's _all_ of them.

For 3 mana, each of these gives 1 mana of any color: [Manalith], [Spectral Searchlight], [Vessel of Endless Rest]

For 4 mana, the [Khalni Gem] makes 2 mana of any color.

For 5 mana, the [Gilded Lotus] makes 3 mana of any color.

...

The [Manaweft Sliver] grants all yoru slivers the ability to generate 1 mana of any color, too.