I think both Rielly (23) and Gardner (26) still have the potential to get better (you can also throw Zaitsev into the conversation and hopefully they can sign him long term as has been speculated) especially on a Leaf team that will be much better over the next few years. Right now they are not in the elite when it comes to defenceman in the NHL and may never be but they are certainly a good #2 and/or #3 (at worst #4 but they are also not being paid as elite defenseman-$5 million for Rielly for another 5 years and $4 million for Gardiner for two more years and Zaitsev's reported $4.5 million for 7 years) on most of the teams in the league. From all accounts, Rielly is also considered one of the leaders in the Leafs dressing room. His character is undeniable and he is only 23 years old!Yeah, I think the young Leafs still have lots of upside. The question is where they will plateau? For example, I think Rielly (not Reilly) and Gardner have plateaued and don't have further upside.
Brett Burns is considered one of the top 3 defenseman in the league and he is 32 years old. Not saying Rielly is as good or better than Burns right now (I don't watch Burns that much to know much about him) but I would never make a one for one trade for Burns with Rielly going the other way. Rielly is only 23 years old and is still learning on a young Leafs team both upfront and on defense. When the front end gets better with experience, the back end will only get better, especially if they are able to get a true #1 or #2 defenseman.
It takes longer for defenseman to reach their potential in the NHL and even though Rielly has been in the league for awhile now, he started off at a young age and on bad Leaf teams (remember the Phaneuf years!!!).
Imagine if Kadri was traded off and with the year he had in 2016/2017 on another team! All it took was maturity (on and off the ice) on Kadri's part and the team putting him in a role that was best suited to him and the game he plays. Most importantly, he has the trust of his coach and upper management as evidenced by his team friendly long term contract.
I really like the future of the Leafs and with one or two years more experience for their core players and the addition of one or two more defenseman (a true number one or at least a strong number two and three), they will become perennial Stanley Cup contenders.
2016/2017 is just the beginning for this Leaf team and management to know where they truly are compared to the elite teams in the league. Making the playoffs was a bonus and will only serve to give the young Leaf players the experience needed to be successful in future years. Just as important, the "core" young players are gaining this experience together and this can only be seen as advantageous in growing stronger as a "team".