First off I was talking about forwards. We are well positioned organizationally for turnover on D.
At forward We have no one on the NHL roster under 25 except for a call up that will be returned to Belleville when Thompson is back. You listed a bunch of prospects who are in junior or Europe and prospects at the top of the next draft. We have the oldest forward group in the NHL and it's not really close. Having some of those guys gradually make the club over the next 4 years is good but we haven't added a forward in 3 years. Dzingle is in essentially his 4th pro year, Stone and Pageau in their 6th.
The guys you listed have the following pro experience (and aren't on the roster.
Gagne - In his 2nd pro year
Perron - In his 2nd pro year
White - In his 1st pro year
Chlapik - In his 1st pro year
So for the 4 years between Stone/Pageau and Perron/Gagner we have Ryan Dzingel to show for it.
Our misses (top 3 rounds at forward) or traded players in that period 2011-present
2017 - 1st rd Shane Bowers (Duchene Trade)
2016 - 2nd rd Jonathan Dahlen (Burrows Trade)
2014 - 1st round pick traded (Ryan Trade)
2013 - 1st round Curtis Lazar (oops - not sure we screwed up his development, think he was just overrated), 2nd rd (Bishop Trade)
2012 - 2nd rd pick (Turris trade), 3rd round Jarred Maidens (UGH)
2011 - 1st rd Zbad (Brassard Trade), Puempel waste, Noeson (Ryan trade no big loss), 2nd round Prince waste. (Interesting this draft gave us Pageau, Claessen, McCormick and Dzingle).