Something not mentioned that makes the duration of the crossing closure at Paignton longer, is the need for trains that arrive into Platform 1 having to reverse back towards London, then moving across into Platform 2. When I was last there a XC train departed P2, with a 158 departing P1 simultaneously. However, the crossing remained shut until the 158 driver changed ends and shunted into P2, at least doubling the duration of the closure. If Paignton ever gets remodelled to allow trains to depart towards Exeter from both platforms, or all P1 arrivals have to reverse into Goodrington sidings before entering P2 (IETs already do this), that would significantly reduce how long that crossing is shut for.
However, the above wouldn't have prevented this particular incident (though the less time crossings are closed, the lower risk of any obstructions like this).