The only thing id like to see, electronically in software speak is get everyone in a standardised source code. Give the customers the same code as their factory counterparts and thus enabling them to maximise their ERS and Brake By Wire capabilities as well. I have heard some engineers say this will bring back the top teams by a a few tenths in lap time, but the mid pack will be able to gain about second in time quite easily through software integration.
Personally, id allow the manufacturers the whole of 2016 to develop with no restriction. But 2017 would be restricted even further, more or less homologated from the beginning, allowing each manufacturer no more than 10 tokens per season for every season after that. However, for every season, the cost for each customer shall not exceed €15m for the power unit and the customers have to be able to get access to upgrades at the same time after their works counterparts.
The V6s are not a disaster, they just have not been thought out correctly from a technical stand point, but a sporting stand point. Personally, i would have a 'Engine Title' where the points accrued from the top 3 cars from one engine manufacturer will give them something extra, not sure what yet. However, it means they have to look after their customers as well as the works side. Penalties could be where the 'engine title' has 5 points deducted per component used over the 4 or 5 per season.