Alex Lifeson owns one of the most gigantic one-guitar sounds ever.
Alex had the luxury of playing with one of the most prolific bass players on the planet.
That would be my advice to the OP. It's a mixture of creating a bigger sound stage but also the bass player stepping up to the plate. ZZ Top is another great example. Dusty Hill may not have been Geddy Lee but his playing was a lot more ferocious that you might think if you really listen. He understood his role in the band. Also, it's one thing to play in a three piece band from the start and entirely another thing to play is a four piece band that suddenly becomes a three piece. You don't miss something that was never there.