Rush has witnessed plenty of change since he joined the Blues following the 2005 Grand Slam and he reckons Welsh rugby is in better health than ever.
"There have been huge changes in Welsh rugby since I arrived," said Rush, 34.
"I look at the players being produced compared to when I first came, the sheer athleticism of them shows the academy systems are really working.
"When I first came here, coming from New Zealand you were a few steps ahead, but they're second to none in world rugby now."
One of the other biggest changes Rush has noticed has been a shift in mentality, something he believes has been instilled by Warren Gatland and passed down through the ranks.
"As a Kiwi you are brought up in a certain way where it's not about going out and trying hard, it's about going out and winning - that's what you're judged on," said Rush.
"Warren is really starting to tune that mentality into the international guys. They're developing a real mental edge.
"They don't just want to compete they want to win. You could see that with the Test series with Australia. They were bitterly disappointed to lose but that's good.
"Wales Under-20s success at the Junior World Championship and their victory over the Baby Blacks also demonstrates that."
Rush has had a major impact in the Welsh capital and leaves a giant pair of boots to fill at the Arms Park.
But he reckons the Blues have the players to fill the void and in particular Durban-born Andries Pretorious, who qualifies for Wales this year.
"Luke Hamilton and Ellis Jenkins, from Wales Under-20s are options and of course Andries is there," added Rush.
"We can fill the position with Andries and the other guys. It's a massive year for him and he will be more excited than anyone about the prospect of getting out there.
"He's a very dedicated bloke. He qualifies for Wales soon and will add to that depth Wales are developing in a lot of positions."