4mil for a 3rd pairing guy. sure.

He's been outstanding alongside Skjei, you of all people as a Rags fan should know that.

I am a Rangers/Islanders fan but that means i've seen Smith play. I see him as a 3rd pairing guy. I know 4mil is too much for anyone, but if you're talking how other players get paid, 4mil for Brendan Smith makes no sense to me.

Lose Dumo and replace him with worse Smith...at similar value all to protect Hornqvist for one more year

No dice

I like Dumo. He's done an outstanding job w/Hainsey, and last year he played very well w/Lovejoy. He's great if you put him on a shutdown pair. However, he hasn't played very well w/Schultz, and his numbers alongside Letang are no better than those of anyone else. He could be effective next to Cole on the bottom pair, but why pay 3-4mil for a bottom pair dman? While I don't think Smith is a good as Dumo, the numbers (corsica.hockey) show that he's clearly outperformed a 3rd pairing role, thus making him a top 4 dman. He also wouldn't require expansion protection if you sign him in UFA. Maatta & Smith could switch spots if Smith proves he's not an adequate partner for Letang, but the reality is the Pens don't have a true top pairing guy on the roster who can complement him, so it will have to be by committee. Paul Martin was that guy, and the Pens let him go at the right time, but they never really replaced him, either. They spent the money they'd paid Martin (and, to a lesser extent, Ehrhoff) to Phil. I'm not complaining; Phil's the man, and it won us a cup. Just pointing out that it left us pretty weak at LHD.

The Pens thought Maatta would be that guy but he hasn't developed yet. Dumo is younger than smith. and will sign for under 4mil. You don't throw away a 25 year old minute eating defenceman who is 6ft 4 to sign someone who mostly has been mediocre for his career. Sorry the Pens may be weaker on the left side but that is not because of Dumoulin.
And Corsi isn't really true show of skill or ability. Smith has good Corsi as #3 pairing but put him in the top 4 with increased minutes and responsibility and he probably wouldn't look as good.