ExpandAll2[exp] is similar to ExpandAll, but much faster on simple structures.
Benchmark against the standard ExpandAll
exp = Sum[p[i], {i, 1, 100}] Sum[q[i], {i, 1, 1000}];AbsoluteTiming[res1 = ExpandAll[exp];]\{0.679579,\text{Null}\}
AbsoluteTiming[res2 = ExpandAll2[exp];]\{0.250011,\text{Null}\}
res1 === res2\text{True}
ClearAll[exp, res1, res2]