I've just started DMing a D&D 5e game and we're playing fairly fast and loose with the rules since my party's in it for the roleplaying more than the specifics.
One of my players is a half-orc fighter wielding a two-handed warhammer and a shield. She asked if she could (in a single round) stow her shield, take a strike with her warhammer (with both hands), then get her shield out again. From what I can tell in RAW this wouldn't be allowed since it would take essentially three actions - one to switch to the warhammer, one to attack, and one to switch back to the shield, but I allowed it at the time since I didn't see any reason not to as a house rule. We've been treating switching weapons as a bonus action anyway so in our eyes it's just an extra bonus action per turn and it does make it impossible for her to do anything else on a turn when she chooses combat.
I don't particularly care if I'm right or wrong on the rules here (since we're fine with house rules) but I am wondering if allowing this will cause me trouble later on. Are there downsides I haven't predicted to her having her shield always accessible in every round of combat going forward? It bumps her AC but as the lone tank in a 2-player L4 party they're fairly underpowered in general and this seemed like a decent balance, but that may be my naivete talking.
The biggest "issue" I predicted was just that it would give her basically a permanent bump to her AC. As addressed though, since she's the sole tank and I've still managed to hit her at least a few times in most encounters I don't see this as something that can't be dealt with by boosting monsters a little to match, if needed.
I'm mostly concerned this might affect things in later levels that I haven't researched yet; this is my first time playing D&D myself rather than watching others and I'm far from fluent.