I think the historical consensus is that Arthur did everything Garfield was supposed to do.
Counterfactual history (invented by Herodotus) can be fun, even if unprovable. Would John Adams have purchased Louisiana? Would Henry Clay have gone to war with Mexico? Would Charles Evans Hughes gone to war with Germany? What would Europe have looked like in 1948 if FDR had died one year sooner and Henry Wallace had won the election of 1944--France, Italy and Greece might have been Communist countries. Would Richard Nixon have botched the Bay of Pigs invasion and encouraged the coup against Diem?