I don't take the position that Renegade choices SHOULD lead to a better war effort, but I certainly see a lot of ways that the Renegade decisions could have been... if not better, at least tied in effectiveness.
The biggest one, of course, would have been the Renegade Council. I really think Bioware missed the ball with that one, because it passed up one of the easiest justifications for the Alliance's claim to power, but also to highlight it's isolation.
The Human Council could have publicly revealed the existence of the Reapers... and then be dismissed by Council races for making it up to justify the coup.
It would easily have played a number of the ME1 themes and even subtle ME2 themes (that the Alliance/Humans do recognize problems and are quicker to try and react to them), would have continued the grounded ME2 themes (the Alliance is too busy/outvoiced by the Paragon Council to address the Terminus issue), and highlight the Alliance's isolation after it seized power (no one believes Humans crying Reaper). It would be the position of a dominating Humanity trying to drag the unbelieving galaxy towards preparing for the Reapers.
This wouldn't even have to count as a BETTER galaxy, but one equally prepared but in a different fashion. An equivalent to the Paragon Council, rather than an inferior galactic position.
Where the Paragon Council suffers fewer fleet losses against the Geth, the Human Council sees a galaxy arms race that rebuilds the strength. If the Terminus historically hates the Paragon Council, it still has an open mind in ME2 towards the new Human Council.
While the Paragon Council has cooperation and flexibility, the alien races don't recognize the threat and muzzle the Alliance.
While the Renegade Council is isolated and not believed, it's actively preparing as much as it can from its position of strength.
That alone would have gone a long way towards making the Renegade position equal in terms of the biggest choice of ME1, without making both the same disbelieving Council.
Other Renegade choices that seemed bad/indifferent at the time could also have provided forms of equalization.
On Feros, the death of the Human colony could have seen the Alliance focus more on the defensibility of future colonies rather than the more rapid, risky development. More Alliance patrols, larger garrisons, all with the view towards allowing colonies to hold out for longer. Fewer but stronger colonies.
On Noveria, the destruction of the Rachni Queen, and the subsequent coverup of the Rachni, could have led to the Alliance/Council blackmailing the Noveria corporations. Whereas a Paragon Spectre loosing the Queen makes the Council complicit in the risk, the 'kill the Queen' Spectre allows the Council/Alliance to twist arms or else leak the results. The Noveria Executive Board gives more technology at better rates, strengthening Council troops and fleets.