Vanguard's cheapness is a main virtue of them; if you want a squad kitted out, just take Honour Guard and save yourself the effort (Vanguard will never be as good in a fight as Honour Guard for the points, so you have to capitalise on their greater mobility and keep them cheap). I'd bring them as 5-man units with a Relic Blade on the Sergeant and maybe 2 Lightning Claws on other guys. I don't like Storm Shields on Vanguard; against a lot of things, it's no better than your armour, and at only T4 3+ it's going to be the Bolters and punches that kill you. You can always get cover until you're in melee anyway. The exception would be on the Sergeant so he can take some punches in challenges, but even then it's not an auto-take.
Decide what you need them to do and give them the bare minimum they need for that job. Vanguard make good harassers - killing Lootas and Devastators and that kind of thing - due to their great mobility (12" move and re-roll Charge distances is great). 2 special melee weapons are probably enough for a 5-man team. If you want a heavy duty combat unit, they're not really the right tool for the job; Honour Guard and Assault Terminators will end up performing better in that role, I feel.
Also, I'm sorry your Chapter Tactic is so awful