I'm really glad private matches with friends are available. It's a shame that you can't tweak the rules at all, but I doubt I would personally mess with them much even if I could. While I will be using Skype or other voice chat options via PC to communicate with my friends, I'm positive there will be times when I really want to play but I can't get a full team of friends to join me, in which case I will be playing with randoms, and voice chat would certainly help us all work together. However, I don't usually communicate with randoms myself, so it's not going to bother me much. Regardless of the fact I wouldn't make much use of voice chat with randoms, having the option to do so would be great. It's a very minor con to me, but admittedly there may be times where my team is trying to communicate with me and if they're doing so, I feel like I should be talking as well.
I think it's entirely possible voice chat could be added into the game in a later patch. If it is, I think it should be optional as it is in Smash and Mario Kart. Press a button to turn it on/off. The quality won't be spectacular by any means, but I can acknowledge that some people would still love having it and make use of it frequently.
The price of the game here in the UK is roughly £35, and most new titles cost anywhere between £40-50. I'm happy paying that price for this game. I think a lot of people would be much happier with the price and overall game if some of the DLC ended up being free. Maybe a new game mode or two, along with a couple of maps to go with them. I also think more people will come around once the game is released, assuming the online connection is stable and the matches look very fun to people, even without voice chat. Once people can truly see the full game in action, it may influence their decision. Obviously it might sway them in the direction of not buying, but hey. All the cool kids play Splatoon.