For ODI, he makes the team on batting merit - we have seen enough of PAK batting by this time not to expand on this. Problem is, people judges him on hypothetical possible most adverse condition & perceived struggle - so, his ENG/NZ stats stands on face value, but SAF stats comes with footnote regarding condition/opposition/wind, grass, water, sun light .... A player should be given his best chance to succeed, without costing team interest - there is no point discussing Malik's batting at 3 or in ENG or against fast bowling. As a player, he is one of the fittest, among the best runners, spin players & he comes with good cricket sense that helps the team. Along with his bowling - he qualifies the first hurdle of Captaincy - he makes the LO team on players' merit; which is not true for Azhar.
Would he been successful as Captain in terms of W/L - I don't know. To a certain extent, a Captain is as good as his team, but not other way is always necessarily true. But, there is stats beyond direct W/L, for which, I can back him to do better - take random matches under Azhar; almost every time, teams have got out of jail - be it batting first or second, which can't be coincidence. Check bowling charts - you'll see glaring misses in utilizing key bowler's quota in any particular match - for example, last match, after Maxi got out; Aussie WK, who happens to be a lefti, added 100 with 3 tail-enders, one of them also being lefti - and MoHa was under bowled 3 overs ...... one of many, many such I can list.
This is a poor PAK side, even Imran won't have achieved much; but I back Malik to do better than the 3rd ODI against Poms in UAE, the Pallekelle one, the 1st ODI against BD, the 1st ODI against NZ - these are perfect examples, how you allow a side to get out of jail from back on mat.
On tactical terms, Malik is among very few PAK players in recent times, who has played in Global leagues - BBL, CPL, PSL, BPL ..... with global top talents & under Professional set-up/Captains - he has to be better than anyone whose field is Inter Department List A & level is Kamran Akmal - the Wapda Captain.