I don't know about national title, but it could have been the best team that A&M ever fielded.
That team went 17-9 and ended up ranked #18 (was ranked as high as 9 early in the season), which doesn't exactly scream "one player away from greatness," but consider...
Lester ended up the previous year ranked #8 in the country and was only getting better. His leaving also broke up the #3 doubles team in the country (with Ante).
So you would have had Lester at 1, Jerry at 2 - and mind you this isn't the shadow of his former self, burned out on tennis Jerry, but the phenom that he was when he first got here who ended up the season ranked #14 as a freshman.
At 3 you have Ante - pretty nice to have an all-american and a guy who had been ranked as high as 6 in the country playing 3 for you. That would make, arguably, the strongest 1-2-3 in the country. Definitely a team that could give Ze Germanz at Baylor a run for their money.
At 4-5 you would have had Wooten and Joelson. Wooten was really coming into his own (what in the world has happened since then?!?). He really held down the fort at 3 that year and even managed a ranking at one point. He could have only done better at 4. Almost the same exact story for Joelson, who went 8-1 at #4 that year, while struggling (1-5) at 3. You've got to think he would have gotten it done at 5.
Dakki might have stayed motivated and not tanked if he was on a better team. He had all the talent in the world, but it's hard to be motivated when you're nearly 30, playing with a bunch of kids, knowing that you're playing for 2nd place to Baylor. In any case, you think that a guy who was ranked 103 in the preseason poll might have been able to win some at 6. He was certainly capable of it, injured, demotivated -- whatever.
Our doubles lineup would have been Lester/Ante at 1 (automatic), and some combination of Joelson, Wooten, Jerry, and either Bain or the Malm - of which you could make some very solid teams.
We had a lot of 3-4 losses that year (UVA, Duke, USC, Tech, and a 2-4 loss to OSU). There is obviously no way of knowing how having Lester would have affected those outcomes, but you have to think that those were all winnable with Lester. That puts our record at 22-4 with our only real beatings being at the hands of Pepperdine, LSU, and Baylor (twice). There is really no way of knowing how positively it might have affected the team had Lester stayed and allowed everyone to play one spot down. It would have still been tough to beat Baylor that year, but I think that we could have definitely made it further in the tournament, as the better record might have put us further away from them in the draw.