As long as you think the units you take aren't just there to die and can reasonably do some damage somewhere with other units to cover their weakness's then you shouldn't have a problem.
Not a tournament player, mind, but generally striking a balance works fairly well as long as you know you can get the most out of your army and cover as many different scenarios as possible. You're not always going to be playing
KP and have the power to sweep an opponent off the board. Of course that depends on what you mean by balance: variety of units, not taking
OP units, not spamming special weapons, being able to deal with objective and
KP scenarios etc. Personally, taking my nids as an example, I make it as fiendish as possible with two trygons, blobs of stealers and the like; but, I also take twenty gargoyles because I like the models and they don't exactly become a major weakness in the army. I've even brought down bloodthirsters with the wily hawkmen. So you could take strong elements to compensate for more fluffy/eccentric units if thats your thing and you never know luck can always strike you.
Automatically Appended Next Post: ObliviousBlueCaboose wrote:I concur with fotta.
I do find it easier to play a balanced list, the infantry hole up in cover, shooting at targets of oppertuneity, while the mechvets charge forward, ready to storm the enemy lines. All the while leman russes support the charge and a manticore provides long range support.
yeah this guy has the right idea. I basically use this 'tactic' every army from nids to dark eldar since you cover a lot of bases.