@Archtyrant:
Haha yeah sorta.. I quite agree with Ubiq too.
Though, I think the OP's intentions were: if Ace had not had his Logia powers, would he still have been able to beat Van Auger and Burgeioss? (however you spell his name)
If the situation goes in the same manner it did, then the answer is decidely no. Sans Logia powers, Ace winds up with a bullet in his brain, heart, stomach, crotch, and kidneys before having a building dropped on him.
If Ace is a bit more cautious, then it's up in the air. I wouldn't be the least bit surprised if Burgess weren't quite a bit stronger than Ace physically. If nothing else, he's physically stronger than Arlong, who is himself no weakling, and incredibly tough as he shrugged off being hit by Hikan.
Augur… well, it depends on how fast Augur is. If he can put some distance between himself and Ace, then it's only a matter of time until he kills Ace with his sniping.
@blacky:
Crocodile did the same. He even explicitely said that a devil fruit ability needs to be trained and that he (also) trained 10 years to become this powerful so it is safe to assume, that he was also weak at first.
The training was in reference to honing his Devil Fruit. Most people are simply content to have a Fruit and don't put much real thought into how to use it. Again, Crocodile is remarkably resilient to physical attacks as shown by his second fight with Luffy; either he's kept up his physical training on top of everything else or he was fairly strong to begin with.
Again, considering the rarity of Devil Fruit to begin with and the rarity of Logias in particular, it seems likely that you have to be fairly powerful to begin with in order to acquire one. Otherwise, you're not likely to find it and claim it for your own. Look at what happened to Satch for instance: someone more powerful took it away from him.
@Phenomenol:
Your post is great Ubig but Ener was physically weak without his Logia powers. As you can see it was very difficult for him to take damage from Luffy's attacks. Ener was a blow away from dying by Luffy and for all intents and purposes Ener was dead after the Reject Dial and just restarted his heart.
Again, look what Reject did to Giant Jack: it blew the beanstalk to bits. Yet it didn't have any lasting impact on Ener; same for Luffy's attacks. Ener was obviously caught off guard whenever he was hit, but Luffy still hit him several times without any lasting impact. Ener even managed to stop Gum Gum Gatling just by grabbing Luffy's arms; that doesn't suggest weak.
One more thing beyond all that: Seastone is supposed to be stronger than diamond is it not? Then how did he smash Wiper's Seastone jetskates so easily? His powers won't work it, so it has to be pure brute force does it not?