That's one way to look at it. I thought Alonso fit our power need, and while there are many ways to build a WS team, the last 4 Sox ring teams had 2 power bats. This one has none, and Breggie added would still have left us with none.
It's a close call, but to me Alonso's offense has been more consistent, and he's a little younger. OPS+ last 5 yrs:
134 Alonso (133>146>123>122>144)
123 Bregman (113>134>122>116>128)
The defense part goes heavily to Breggie, and it's harder to add a good 3Bman than a 1Bman, as the Contreras trade showed.
We have Contreras, now, anyway, so it matters little. I'm not upset about Alonso, either, because of Contreras.
If we lose out on Suarez or trading for a #2, I'll look back at Polanco as the one we could have done something about- maybe Suarez, too.