Gabon and Chad plus the DRC and Uganda are eminently doable right now, if you are willing to sacrifice the level of luxury offered by the likes of Singita which strike me as singularly unappealing - I think it was perhaps Lyn Middlehurst who coined the phrase 'Spafari' which sums up Singita for me. In fact, I think the whole South Africa safari offering is more of a private zoo. As far as places like Gabon are concerned, I would always say Go Now before the spafari crowd shows up. Aman was once threatening a lodge in Gabon where elephants and big cats are rumoured to be found on the Atlantic beaches, on sun loungers sipping pina coladas. I think Madagascar is lost as a wildlife destination due to a catastrophic deforestation programme, so you are left with lemur reserves.