is a halfway decent card that is being played in top tier standard midrange and control decks to survive against aggro and beatdown decks.
In multiplayer there is a greater chance of it giving both goodies but it still has flaws:
If you are ahead, it does nothing. This isn't neccesarily a bad thing because win more cards (the exact opposite) are bad so some will say this is good but a card that does nothing at any given time in a game that you want to win is never good. I will try to clarify that too long sentence a bit: A Wrath of God
also does nothing if you are loosing to a creatureless board but it isn't a bad card because that hardly ever happens. If you are going to win, you should be ahead at any given time and at that time a Wrath of God
generally still does something (eventhough you generally don't play it because it will destroy your lead) but Timely reinforcements
at that time does nothing (even if you wanted it too do something).
If you are losing and behind on life and creatures, you will generally not mind topdecking this. But it is generally not a solution to your problem. 3 1/1's aren't going to stop that Akroma, Angel of Wrath
or most simpler critters. You can chump block some units but it still generally doesn't get rid of the cause of the problem. Something mass removal or any kind of removal / big critter does do.
In other words: this card generally doens't help you win. It just makes you not loose a little bit longer but in multiplayer every round the game goes on your opponents are drawing more cards combined than you, they have more combined mana available, etc, etc so unless you have a long long game plan for surviving all those extra resources of your opponents you shouldn't make the game go on longer than neccesary.
Lastly I would not play this card 4 times in a deck (unless I am playing a 1vs1 tournament and then only after sideboarding against aggro decks). Multiples of this card can be even deader for a long time than a doubly drawn legendary permanent. Yes, both often eventually become usefull but a card that is dead for any amount of time is something I prefer to prevent.
I find it cool that they printed this card because it is a cool card with great flavour and style. It is great in midrange and control decks in 1v1 but in multiplayer I don't think it shines even brighter.