Speaking in The Scotsman, Rennie said: "I believe we will be a lot better than we were last year as we're further down the track. We've had a lot of detail in our pre-season and the coaching group has done a great job. We will have a better side than we had this time last year."
Warriors have been fairly quiet on the transfer front. Nick Frisby and David "Tevita" Tameilau are two of the more high-profile additions but the Warriors also have players who missed big chunks of last season with long-term injuries and having the likes of Alex Dunbar, Adam Ashe and Oli Kebble back in harness will feel like an injection of fresh blood.
"We had 16 guys (sign for the club) the year before," Rennie pointed out. "A number of them are on two or three-year deals. There are a lot of Scottish guys we are keen to keep so we can manage them.
"Tevita comes in as we wanted another big ball carrier. Hopefully we'll get more out of Adam Ashe this year. We are happy with the squad and the depth."
Rennie has always said he picks on form, as he did last season when dropping Ali Price from the matchday 23. Currently recovering from a tweak to his groin, the scrum-half will be hungry to regain his starting spot from George Horne.
George's older brother Peter is sitting out the pre-season matches, in line with Scotland squad protocols, so he will not be available for selection until the first round of the PRO14 fixtures next weekend. He misses Friday's friendly against Northampton.
Adam Hastings will start at ten against the Saints in Glasgow's second pre-season warm-up. Glasgow put 50 points past Harlequins on Saturday and, although he was only on the field for a brief time, stand-off Hastings appears to have grown in stature since making his Scotland debut over the summer.
"We decided to wrap him (Hastings) up in cotton wool as he's starting this week," Rennie said.
"We can't play Peter Horne until round 1 but Adam has been excellent in training. I think he has grown in confidence. He's demanding, clear in his role, competitive and fit. He's in really good nick.
"There's no doubt that a lot of young men get their opportunity with Scotland a bit quicker than they would in New Zealand, where you have five Super Rugby teams. They have to learn quickly.
"I look at George and Adam, and they are outstanding trainers and keen to learn. They want to be challenged. It's our job to accelerate their learning. We have more good, young kids coming through, as we saw at the weekend."