No. That seems like a fairly mild addition, in the variety of low grade summoning magic.

More specifically, just "adding" additional damage or attacks (or any numerical bonus) will never "fix" a low Tier class (one with few resources, which allow the class to do a variety of things well).

A Tier 4 or lower class will never be able to get out of Tier 4 without a subsystem of abilities which can be changed each day, selected from a broad list, and allow you to fill a variety of roles. In 3.5, those options are magic, psionics, incarnum, vestiges, and maneuvers, plus the various homebrew systems floating around.

Soulknife's are one of the most homebrewed/fixed classes out there. A brief survey of the the forum here will probably give you dozens (hundreds?) of fixes. The one offered by Dreamscarred Press (for Pathfinder) is pretty good. (And I'm partial to my War Soul, if you're willing to listen to a shameless plug and learn Incarnum).