From what I saw yesterday, the answer to that question is probably no.
Firstly There was still the very long congested queue out of the park to the end of Winkfield road and this was an hour after park close.
Secondly, I've looked around the road to see if they could potentially widen it. Whilst they could make the road two lanes towards the Legoland end of Winkfield road, the rest near the houses doesn't look possible due to the close proximity of houses there.
Two additional things to note are that on the LegolaƱd exit road from the park, the direction board now says the M4, M3,M25 etc. Are on the right whilst the left one now just says local traffic which despite this attempt diversion, still doesn't seem to be working so well.
Also, there was a (Texaco) petrol station on the other end of the road (on the M4 side) which appears to have closed down and become a car dealer. Maybe this is to potentially reduce traffic on that road or just a coincidence.
Seeing as the park haven't opened this year's main addition yet (Heartlake City), unless you count the rethemed driving & boating school rides, they may have a chance seeing as this shows the patk is busy and popular regardless of new additions.