They are very far from deciding a new engine formula and based on the last 25 years of F1 squabbles, excuse me if I predict that the majority of future changes will be ill-conceived and expensive.
With more small teams killed off in F1 there are less customers to sell their ridiculously priced engines to (which helped killed them in the first place), thus huge costs which cannot be offset, even if development is cheaper than the last change.
Engines aren't really the problem - manufacturers are much happier binning money on engines than on aero, it shows the world how clever they are if they can make the winning engine. The aero expenses are massive, and only rising as testing is cut back in favour of simulation. F1 aero doesn't say anything of any interest about the people paying the bills but, as aero knowledge increases, returns diminish and the cost of obtaining an advantage increases.
The F1 teams themselves (who set the rules) basically depend for their existence on a their expertise on this small, irrelevant corner of aerodynamic analysis - how air flows over an open wheel, open cockpit car with a plank nailed to the floor. Take that aspect away (no wings, big slicks formula for instance) and who needs McLaren? Or Williams? Or 'Mercedes' or 'Red Bull' or 'Lotus', let alone 'Force India'?
So, given that turkeys won't vote for Christmas, the teams all moan about how engines make F1 unaffordable, while at the same time getting together and formulating rules that constantly ramp up the cost and complication of the only aspect of the sport they can use to justify their own existence.
However much money they get, the teams will spend as much as they can on aero to maintaining the competitive advantage they need to exist. If FI had a budget of £20 million less than they do and engines free, they would budget the lot for chassis (basically aero), then borrow for contingency spending, and probably go bust anyway.
The only likely result of significantly cheaper engines would be a few more teams entering (and probably failing fast) as the entry barrier would be lower - again, not something the current teams are keen on. If the technological and financial barriers become ever higher, their position becomes ever better. So long as they can pay to survive.