It's movable in version 2.1.6-classic.

Went ahead and tested this, with both alpha2 and alpha3 i can move the talent frame. You sure you havent accidentally disabled it in the options?

Or do you maybe have other addons that might affect that frame?

I finally got around to debug this, and found that DejaClassicStats is interfering with BlizzMove. More specifically, it hooks into the OnShow and OnHide of the talent frame:

DCS_BLIZZ_SKILL_PANELS = {
	"TradeSkill",
	"Craft",
	"Talent",
}

local DejaClassicStatsExpandEventFrame = CreateFrame("Frame", "DejaClassicStatsExpandEventFrame", UIParent)
DejaClassicStatsExpandEventFrame:RegisterEvent("ADDON_LOADED")

DejaClassicStatsExpandEventFrame:SetScript("OnEvent", function(self, event, arg1)
	if event == "ADDON_LOADED" and arg1 == "DejaClassicStats" then
		self:UnregisterEvent("ADDON_LOADED")
		for k, v in ipairs(DCS_BLIZZ_SKILL_PANELS) do
			if _G[v.."Frame"] == nil then
				if _G[v.."Frame"] == "DetailsFrame" then return
				else
					LoadAddOn("Blizzard_"..v.."UI")
					_G[v.."Frame"]:HookScript("OnShow", function(self)
						if PaperDollFrame:IsVisible() then
							local checked = gdbprivate.gdb.gdbdefaults.dejacharacterstatsExpandChecked.ExpandSetChecked
							if checked == true then
								DCS_CharacterFrame_Collapse()
							end
						end
					end)
					_G[v.."Frame"]:HookScript("OnHide", function(self)
						if TradeSkillFrame:IsVisible() or CraftFrame:IsVisible() or TalentFrame:IsVisible() then return
						else
							local checked = gdbprivate.gdb.gdbdefaults.dejacharacterstatsExpandChecked.ExpandSetChecked
							if checked == true then
								DCS_CharacterFrame_Expand()
							end
						end
					end)
				end
			end
		end
	end
end)

Toggling the setting enables the frame to be moved (though breaking DejaClassicStats' auto-hide) until a reload.

Seems its because some addons forceload load on demand addons, and when they got loaded between two certain moments during loading, they would go unnoticed as being loaded in our addon, added a loop that should prevent this in v3.0.8.

Same in 3.0.1. Upon logging in, I am unable to move the Talents window. It is checked in the Blizzard_TalentUI panel, and toggling it back and forth allows the Talents panel to be dragged again. No errors are thrown that I am seeing, etc.

@tuftelien does toggling the talentframe in the options also make it draggable for you?

Also, could both of you try if this behavior also happens if only blizzmove is loaded?
If it doesn't happen with just blizzmove loaded, it might be an other addon breaking something. So try loading your addons one by one untill it breaks, and let me know wich one it is. That way we can look into a workaround to fix this issue.